Alvaro Herrera wrote:
> I tried patch 0002 today and again there are conflicts, so I rebased and
> fixed the merge problems.
... and attached the patch.
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 2c2da2a..b5c4129 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -296,6 +296,11 @@
</row>
<row>
+ <entry><link
linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link></entry>
+ <entry>extended planner statistics</entry>
+ </row>
+
+ <row>
<entry><link
linkend="catalog-pg-subscription"><structname>pg_subscription</structname></link></entry>
<entry>logical replication subscriptions</entry>
</row>
@@ -4223,6 +4228,98 @@
</table>
</sect1>
+ <sect1 id="catalog-pg-statistic-ext">
+ <title><structname>pg_statistic_ext</structname></title>
+
+ <indexterm zone="catalog-pg-statistic-ext">
+ <primary>pg_statistic_ext</primary>
+ </indexterm>
+
+ <para>
+ The catalog <structname>pg_statistic_ext</structname>
+ holds extended planner statistics.
+ </para>
+
+ <table>
+ <title><structname>pg_statistic_ext</> Columns</title>
+
+ <tgroup cols="4">
+ <thead>
+ <row>
+ <entry>Name</entry>
+ <entry>Type</entry>
+ <entry>References</entry>
+ <entry>Description</entry>
+ </row>
+ </thead>
+
+ <tbody>
+
+ <row>
+ <entry><structfield>starelid</structfield></entry>
+ <entry><type>oid</type></entry>
+ <entry><literal><link
linkend="catalog-pg-class"><structname>pg_class</structname></link>.oid</literal></entry>
+ <entry>The table that the described columns belongs to</entry>
+ </row>
+
+ <row>
+ <entry><structfield>staname</structfield></entry>
+ <entry><type>name</type></entry>
+ <entry></entry>
+ <entry>Name of the statistic.</entry>
+ </row>
+
+ <row>
+ <entry><structfield>stanamespace</structfield></entry>
+ <entry><type>oid</type></entry>
+ <entry><literal><link
linkend="catalog-pg-namespace"><structname>pg_namespace</structname></link>.oid</literal></entry>
+ <entry>
+ The OID of the namespace that contains this statistic
+ </entry>
+ </row>
+
+ <row>
+ <entry><structfield>staowner</structfield></entry>
+ <entry><type>oid</type></entry>
+ <entry><literal><link
linkend="catalog-pg-authid"><structname>pg_authid</structname></link>.oid</literal></entry>
+ <entry>Owner of the statistic</entry>
+ </row>
+
+ <row>
+ <entry><structfield>staenabled</structfield></entry>
+ <entry><type>char[]</type></entry>
+ <entry></entry>
+ <entry>
+ An array with the modes of the enabled statistic types, encoded as
+ <literal>d</literal> for ndistinct coefficients.
+ </entry>
+ </row>
+
+ <row>
+ <entry><structfield>stakeys</structfield></entry>
+ <entry><type>int2vector</type></entry>
+ <entry><literal><link
linkend="catalog-pg-attribute"><structname>pg_attribute</structname></link>.attnum</literal></entry>
+ <entry>
+ This is an array of values that indicate which table columns this
+ statistic covers. For example a value of <literal>1 3</literal> would
+ mean that the first and the third table columns make up the statistic
key.
+ </entry>
+ </row>
+
+ <row>
+ <entry><structfield>standistinct</structfield></entry>
+ <entry><type>pg_ndistinct</type></entry>
+ <entry></entry>
+ <entry>
+ Ndistict coefficients, serialized as <structname>pg_ndistinct</> type.
+ </entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+ </sect1>
+
<sect1 id="catalog-pg-namespace">
<title><structname>pg_namespace</structname></title>
diff --git a/doc/src/sgml/planstats.sgml b/doc/src/sgml/planstats.sgml
index b73c66b..76955e5 100644
--- a/doc/src/sgml/planstats.sgml
+++ b/doc/src/sgml/planstats.sgml
@@ -448,4 +448,145 @@ rows = (outer_cardinality * inner_cardinality) *
selectivity
</sect1>
+ <sect1 id="extended-statistics">
+ <title>Extended Statistics</title>
+
+ <indexterm zone="extended-statistics">
+ <primary>extended statistics</primary>
+ <secondary>planner</secondary>
+ </indexterm>
+
+ <para>
+ The examples presented in <xref linkend="row-estimation-examples"> used
+ statistics about individual columns to compute selectivity estimates.
+ When estimating conditions on multiple columns, the planner assumes
+ independence of the conditions and multiplies the selectivities. When the
+ columns are correlated, the independence assumption is violated, and the
+ estimates may be off by several orders of magnitude, resulting in poor
+ plan choices.
+ </para>
+
+ <para>
+ The examples presented below demonstrate such estimation errors on simple
+ data sets, and also how to resolve them by creating extended statistics
+ using <command>CREATE STATISTICS</> command.
+ </para>
+
+ <para>
+ Let's start with a very simple data set - a table with two columns,
+ containing exactly the same values:
+
+<programlisting>
+CREATE TABLE t (a INT, b INT);
+INSERT INTO t SELECT i % 100, i % 100 FROM generate_series(1, 10000) s(i);
+ANALYZE t;
+</programlisting>
+
+ As explained in <xref linkend="planner-stats">, the planner can determine
+ cardinality of <structname>t</structname> using the number of pages and
+ rows is looked up in <structname>pg_class</structname>:
+
+<programlisting>
+SELECT relpages, reltuples FROM pg_class WHERE relname = 't';
+
+ relpages | reltuples
+----------+-----------
+ 45 | 10000
+</programlisting>
+
+ The data distribution is very simple - there are only 100 distinct values
+ in each column, uniformly distributed.
+ </para>
+
+ <para>
+ The following example shows the result of estimating a <literal>WHERE</>
+ condition on the <structfield>a</> column:
+
+<programlisting>
+EXPLAIN ANALYZE SELECT * FROM t WHERE a = 1;
+ QUERY PLAN
+-------------------------------------------------------------------------------------------------
+ Seq Scan on t (cost=0.00..170.00 rows=100 width=8) (actual time=0.031..2.870
rows=100 loops=1)
+ Filter: (a = 1)
+ Rows Removed by Filter: 9900
+ Planning time: 0.092 ms
+ Execution time: 3.103 ms
+(5 rows)
+</programlisting>
+
+ The planner examines the condition and computes the estimate using
+ <function>eqsel</>, the selectivity function for <literal>=</>, and
+ statistics stored in the <structname>pg_stats</> table. In this case
+ the planner estimates the condition matches 1% rows, and by comparing
+ the estimated and actual number of rows, we see that the estimate is
+ very accurate (in fact exact, as the table is very small).
+ </para>
+
+ <para>
+ Adding a condition on the second column results in the following plan:
+
+<programlisting>
+EXPLAIN ANALYZE SELECT * FROM t WHERE a = 1 AND b = 1;
+ QUERY PLAN
+-----------------------------------------------------------------------------------------------
+ Seq Scan on t (cost=0.00..195.00 rows=1 width=8) (actual time=0.033..3.006
rows=100 loops=1)
+ Filter: ((a = 1) AND (b = 1))
+ Rows Removed by Filter: 9900
+ Planning time: 0.121 ms
+ Execution time: 3.220 ms
+(5 rows)
+</programlisting>
+
+ The planner estimates the selectivity for each condition individually,
+ arriving to the 1% estimates as above, and then multiplies them, getting
+ the final 0.01% estimate. The plan however shows that this results in
+ a significant underestimate, as the actual number of rows matching the
+ conditions is two orders of magnitude higher than estimated.
+ </para>
+
+ <para>
+ Overestimates, i.e. errors in the opposite direction, are also possible.
+ Consider for example the following combination of range conditions, each
+ matching
+
+<programlisting>
+EXPLAIN ANALYZE SELECT * FROM t WHERE a <= 49 AND b > 49;
+ QUERY PLAN
+------------------------------------------------------------------------------------------------
+ Seq Scan on t (cost=0.00..195.00 rows=2500 width=8) (actual
time=1.607..1.607 rows=0 loops=1)
+ Filter: ((a <= 49) AND (b > 49))
+ Rows Removed by Filter: 10000
+ Planning time: 0.050 ms
+ Execution time: 1.623 ms
+(5 rows)
+</programlisting>
+
+ The planner examines both <literal>WHERE</> clauses and estimates them
+ using the <function>scalarltsel</> and <function>scalargtsel</> functions,
+ specified as the selectivity functions matching the <literal><=</> and
+ <literal>></literal> operators. Both conditions match 50% of the
+ table, and assuming independence the planner multiplies them to compute
+ the total estimate of 25%. However as the explain output shows, the actual
+ number of rows is 0, because the columns are correlated and the conditions
+ contradict each other.
+ </para>
+
+ <para>
+ Both estimation errors are caused by violation of the independence
+ assumption, as the two columns contain exactly the same values, and are
+ therefore perfectly correlated. Providing additional information about
+ correlation between columns is the purpose of extended statistics,
+ and the rest of this section explains in more detail how the planner
+ leverages them to improve estimates.
+ </para>
+
+ <para>
+ For additional details about extended statistics, see
+ <filename>src/backend/statistics/README</>. There are additional
+ <literal>READMEs</> for each type of statistics, mentioned in the following
+ sections.
+ </para>
+
+ </sect1>
+
</chapter>
diff --git a/doc/src/sgml/ref/allfiles.sgml b/doc/src/sgml/ref/allfiles.sgml
index 2bc4d9f..255e800 100644
--- a/doc/src/sgml/ref/allfiles.sgml
+++ b/doc/src/sgml/ref/allfiles.sgml
@@ -34,6 +34,7 @@ Complete list of usable sgml source files in this directory.
<!ENTITY alterSequence SYSTEM "alter_sequence.sgml">
<!ENTITY alterSubscription SYSTEM "alter_subscription.sgml">
<!ENTITY alterSystem SYSTEM "alter_system.sgml">
+<!ENTITY alterStatistics SYSTEM "alter_statistics.sgml">
<!ENTITY alterTable SYSTEM "alter_table.sgml">
<!ENTITY alterTableSpace SYSTEM "alter_tablespace.sgml">
<!ENTITY alterTSConfig SYSTEM "alter_tsconfig.sgml">
@@ -80,6 +81,7 @@ Complete list of usable sgml source files in this directory.
<!ENTITY createSchema SYSTEM "create_schema.sgml">
<!ENTITY createSequence SYSTEM "create_sequence.sgml">
<!ENTITY createServer SYSTEM "create_server.sgml">
+<!ENTITY createStatistics SYSTEM "create_statistics.sgml">
<!ENTITY createSubscription SYSTEM "create_subscription.sgml">
<!ENTITY createTable SYSTEM "create_table.sgml">
<!ENTITY createTableAs SYSTEM "create_table_as.sgml">
@@ -126,6 +128,7 @@ Complete list of usable sgml source files in this directory.
<!ENTITY dropSchema SYSTEM "drop_schema.sgml">
<!ENTITY dropSequence SYSTEM "drop_sequence.sgml">
<!ENTITY dropServer SYSTEM "drop_server.sgml">
+<!ENTITY dropStatistics SYSTEM "drop_statistics.sgml">
<!ENTITY dropSubscription SYSTEM "drop_subscription.sgml">
<!ENTITY dropTable SYSTEM "drop_table.sgml">
<!ENTITY dropTableSpace SYSTEM "drop_tablespace.sgml">
diff --git a/doc/src/sgml/ref/alter_statistics.sgml
b/doc/src/sgml/ref/alter_statistics.sgml
new file mode 100644
index 0000000..35cbc09
--- /dev/null
+++ b/doc/src/sgml/ref/alter_statistics.sgml
@@ -0,0 +1,115 @@
+<!--
+doc/src/sgml/ref/alter_statistics.sgml
+PostgreSQL documentation
+-->
+
+<refentry id="SQL-ALTERSTATISTICS">
+ <indexterm zone="sql-alterstatistics">
+ <primary>ALTER STATISTICS</primary>
+ </indexterm>
+
+ <refmeta>
+ <refentrytitle>ALTER STATISTICS</refentrytitle>
+ <manvolnum>7</manvolnum>
+ <refmiscinfo>SQL - Language Statements</refmiscinfo>
+ </refmeta>
+
+ <refnamediv>
+ <refname>ALTER STATISTICS</refname>
+ <refpurpose>
+ change the definition of a extended statistics
+ </refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+<synopsis>
+ALTER STATISTICS <replaceable class="parameter">name</replaceable> OWNER TO {
<replaceable class="PARAMETER">new_owner</replaceable> | CURRENT_USER |
SESSION_USER }
+ALTER STATISTICS <replaceable class="parameter">name</replaceable> RENAME TO
<replaceable class="parameter">new_name</replaceable>
+ALTER STATISTICS <replaceable class="parameter">name</replaceable> SET SCHEMA
<replaceable class="parameter">new_schema</replaceable>
+</synopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Description</title>
+
+ <para>
+ <command>ALTER STATISTICS</command> changes the parameters of an existing
+ extended statistics. Any parameters not specifically set in the
+ <command>ALTER STATISTICS</command> command retain their prior settings.
+ </para>
+
+ <para>
+ You must own the statistics to use <command>ALTER STATISTICS</>.
+ To change a statistics' schema, you must also have <literal>CREATE</>
+ privilege on the new schema.
+ To alter the owner, you must also be a direct or indirect member of the new
+ owning role, and that role must have <literal>CREATE</literal> privilege on
+ the statistics' schema. (These restrictions enforce that altering the owner
+ doesn't do anything you couldn't do by dropping and recreating the
statistics.
+ However, a superuser can alter ownership of any statistics anyway.)
+ </para>
+ </refsect1>
+
+ <refsect1>
+ <title>Parameters</title>
+
+ <para>
+ <variablelist>
+ <varlistentry>
+ <term><replaceable class="parameter">name</replaceable></term>
+ <listitem>
+ <para>
+ The name (optionally schema-qualified) of a statistics to be altered.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="PARAMETER">new_owner</replaceable></term>
+ <listitem>
+ <para>
+ The user name of the new owner of the statistics.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="parameter">new_name</replaceable></term>
+ <listitem>
+ <para>
+ The new name for the statistics.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="parameter">new_schema</replaceable></term>
+ <listitem>
+ <para>
+ The new schema for the statistics.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ </variablelist>
+ </para>
+ </refsect1>
+
+ <refsect1>
+ <title>Compatibility</title>
+
+ <para>
+ There's no <command>ALTER STATISTICS</command> command in the SQL standard.
+ </para>
+ </refsect1>
+
+ <refsect1>
+ <title>See Also</title>
+
+ <simplelist type="inline">
+ <member><xref linkend="sql-createstatistics"></member>
+ <member><xref linkend="sql-dropstatistics"></member>
+ </simplelist>
+ </refsect1>
+
+</refentry>
diff --git a/doc/src/sgml/ref/alter_table.sgml
b/doc/src/sgml/ref/alter_table.sgml
index 077c003..f3ad5ed 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -119,9 +119,12 @@ ALTER TABLE [ IF EXISTS ] <replaceable
class="PARAMETER">name</replaceable>
<para>
This form drops a column from a table. Indexes and
table constraints involving the column will be automatically
- dropped as well. You will need to say <literal>CASCADE</> if
- anything outside the table depends on the column, for example,
- foreign key references or views.
+ dropped as well.
+ Multivariate statistics referencing the dropped column will also be
+ removed if the removal of the column would cause the statistics to
+ contain data for only a single column.
+ You will need to say <literal>CASCADE</> if anything outside the table
+ depends on the column, for example, foreign key references or views.
If <literal>IF EXISTS</literal> is specified and the column
does not exist, no error is thrown. In this case a notice
is issued instead.
diff --git a/doc/src/sgml/ref/create_statistics.sgml
b/doc/src/sgml/ref/create_statistics.sgml
new file mode 100644
index 0000000..5919a25
--- /dev/null
+++ b/doc/src/sgml/ref/create_statistics.sgml
@@ -0,0 +1,152 @@
+<!--
+doc/src/sgml/ref/create_statistics.sgml
+PostgreSQL documentation
+-->
+
+<refentry id="SQL-CREATESTATISTICS">
+ <indexterm zone="sql-createstatistics">
+ <primary>CREATE STATISTICS</primary>
+ </indexterm>
+
+ <refmeta>
+ <refentrytitle>CREATE STATISTICS</refentrytitle>
+ <manvolnum>7</manvolnum>
+ <refmiscinfo>SQL - Language Statements</refmiscinfo>
+ </refmeta>
+
+ <refnamediv>
+ <refname>CREATE STATISTICS</refname>
+ <refpurpose>define extended statistics</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+<synopsis>
+CREATE STATISTICS [ IF NOT EXISTS ] <replaceable
class="PARAMETER">statistics_name</replaceable> ON (
+ <replaceable class="PARAMETER">column_name</replaceable>, <replaceable
class="PARAMETER">column_name</replaceable> [, ...])
+ FROM <replaceable class="PARAMETER">table_name</replaceable>
+</synopsis>
+
+ </refsynopsisdiv>
+
+ <refsect1 id="SQL-CREATESTATISTICS-description">
+ <title>Description</title>
+
+ <para>
+ <command>CREATE STATISTICS</command> will create a new extended statistics
+ on the table. The statistics will be created in the current database and
+ will be owned by the user issuing the command.
+ </para>
+
+ <para>
+ If a schema name is given (for example, <literal>CREATE STATISTICS
+ myschema.mystat ...</>) then the statistics is created in the specified
+ schema. Otherwise it is created in the current schema. The name of
+ the table must be distinct from the name of any other statistics in the
+ same schema.
+ </para>
+
+ <para>
+ To be able to create a table, you must have <literal>USAGE</literal>
+ privilege on all column types or the type in the <literal>OF</literal>
+ clause, respectively.
+ </para>
+ </refsect1>
+
+ <refsect1>
+ <title>Parameters</title>
+
+ <variablelist>
+
+ <varlistentry>
+ <term><literal>IF NOT EXISTS</></term>
+ <listitem>
+ <para>
+ Do not throw an error if a statistics with the same name already exists.
+ A notice is issued in this case. Note that there is no guarantee that
+ the existing statistics is anything like the one that would have been
+ created.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="PARAMETER">statistics_name</replaceable></term>
+ <listitem>
+ <para>
+ The name (optionally schema-qualified) of the statistics to be created.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="PARAMETER">table_name</replaceable></term>
+ <listitem>
+ <para>
+ The name (optionally schema-qualified) of the table the statistics should
+ be created on.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="PARAMETER">column_name</replaceable></term>
+ <listitem>
+ <para>
+ The name of a column to be included in the statistics.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ </variablelist>
+
+ </refsect1>
+
+ <refsect1 id="SQL-CREATESTATISTICS-examples">
+ <title>Examples</title>
+
+ <para>
+ Create table <structname>t1</> with two functionally dependent columns, i.e.
+ knowledge of a value in the first column is sufficient for determining the
+ value in the other column. Then functional dependencies are built on those
+ columns:
+
+<programlisting>
+CREATE TABLE t1 (
+ a int,
+ b int
+);
+
+INSERT INTO t1 SELECT i/100, i/500
+ FROM generate_series(1,1000000) s(i);
+
+CREATE STATISTICS s1 ON (a, b) FROM t1;
+
+ANALYZE t1;
+
+-- valid combination of values
+EXPLAIN ANALYZE SELECT * FROM t1 WHERE (a = 1) AND (b = 0);
+
+-- invalid combination of values
+EXPLAIN ANALYZE SELECT * FROM t1 WHERE (a = 1) AND (b = 1);
+</programlisting>
+ </para>
+
+ </refsect1>
+
+ <refsect1>
+ <title>Compatibility</title>
+
+ <para>
+ There's no <command>CREATE STATISTICS</command> command in the SQL standard.
+ </para>
+ </refsect1>
+
+ <refsect1>
+ <title>See Also</title>
+
+ <simplelist type="inline">
+ <member><xref linkend="sql-alterstatistics"></member>
+ <member><xref linkend="sql-dropstatistics"></member>
+ </simplelist>
+ </refsect1>
+</refentry>
diff --git a/doc/src/sgml/ref/drop_statistics.sgml
b/doc/src/sgml/ref/drop_statistics.sgml
new file mode 100644
index 0000000..d7c657f
--- /dev/null
+++ b/doc/src/sgml/ref/drop_statistics.sgml
@@ -0,0 +1,91 @@
+<!--
+doc/src/sgml/ref/drop_statistics.sgml
+PostgreSQL documentation
+-->
+
+<refentry id="SQL-DROPSTATISTICS">
+ <indexterm zone="sql-dropstatistics">
+ <primary>DROP STATISTICS</primary>
+ </indexterm>
+
+ <refmeta>
+ <refentrytitle>DROP STATISTICS</refentrytitle>
+ <manvolnum>7</manvolnum>
+ <refmiscinfo>SQL - Language Statements</refmiscinfo>
+ </refmeta>
+
+ <refnamediv>
+ <refname>DROP STATISTICS</refname>
+ <refpurpose>remove extended statistics</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+<synopsis>
+DROP STATISTICS [ IF EXISTS ] <replaceable
class="PARAMETER">name</replaceable> [, ...]
+</synopsis>
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Description</title>
+
+ <para>
+ <command>DROP STATISTICS</command> removes statistics from the database.
+ Only the statistics owner, the schema owner, and superuser can drop a
+ statistics.
+ </para>
+
+ </refsect1>
+
+ <refsect1>
+ <title>Parameters</title>
+
+ <variablelist>
+ <varlistentry>
+ <term><literal>IF EXISTS</literal></term>
+ <listitem>
+ <para>
+ Do not throw an error if the statistics do not exist. A notice is
+ issued in this case.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><replaceable class="PARAMETER">name</replaceable></term>
+ <listitem>
+ <para>
+ The name (optionally schema-qualified) of the statistics to drop.
+ </para>
+ </listitem>
+ </varlistentry>
+
+ </variablelist>
+ </refsect1>
+
+ <refsect1>
+ <title>Examples</title>
+
+ <para>
+ ...
+ </para>
+
+ </refsect1>
+
+ <refsect1>
+ <title>Compatibility</title>
+
+ <para>
+ There's no <command>DROP STATISTICS</command> command in the SQL standard.
+ </para>
+ </refsect1>
+
+ <refsect1>
+ <title>See Also</title>
+
+ <simplelist type="inline">
+ <member><xref linkend="sql-alterstatistics"></member>
+ <member><xref linkend="sql-createstatistics"></member>
+ </simplelist>
+ </refsect1>
+
+</refentry>
diff --git a/doc/src/sgml/reference.sgml b/doc/src/sgml/reference.sgml
index c8191de..aa8a157 100644
--- a/doc/src/sgml/reference.sgml
+++ b/doc/src/sgml/reference.sgml
@@ -60,6 +60,7 @@
&alterSchema;
&alterSequence;
&alterServer;
+ &alterStatistics;
&alterSubscription;
&alterSystem;
&alterTable;
@@ -108,6 +109,7 @@
&createSchema;
&createSequence;
&createServer;
+ &createStatistics;
&createSubscription;
&createTable;
&createTableAs;
@@ -154,6 +156,7 @@
&dropSchema;
&dropSequence;
&dropServer;
+ &dropStatistics;
&dropSubscription;
&dropTable;
&dropTableSpace;
diff --git a/src/backend/Makefile b/src/backend/Makefile
index 7a0bbb2..426ef4f 100644
--- a/src/backend/Makefile
+++ b/src/backend/Makefile
@@ -19,7 +19,7 @@ include $(top_builddir)/src/Makefile.global
SUBDIRS = access bootstrap catalog parser commands executor foreign lib libpq \
main nodes optimizer port postmaster regex replication rewrite \
- storage tcop tsearch utils $(top_builddir)/src/timezone
+ statistics storage tcop tsearch utils $(top_builddir)/src/timezone
include $(srcdir)/common.mk
diff --git a/src/backend/catalog/Makefile b/src/backend/catalog/Makefile
index 3136858..ff7cc79 100644
--- a/src/backend/catalog/Makefile
+++ b/src/backend/catalog/Makefile
@@ -33,6 +33,7 @@ POSTGRES_BKI_SRCS = $(addprefix
$(top_srcdir)/src/include/catalog/,\
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.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_pltemplate.h \
diff --git a/src/backend/catalog/aclchk.c b/src/backend/catalog/aclchk.c
index be86d76..1d71c7c 100644
--- a/src/backend/catalog/aclchk.c
+++ b/src/backend/catalog/aclchk.c
@@ -48,6 +48,7 @@
#include "catalog/pg_operator.h"
#include "catalog/pg_opfamily.h"
#include "catalog/pg_proc.h"
+#include "catalog/pg_statistic_ext.h"
#include "catalog/pg_subscription.h"
#include "catalog/pg_tablespace.h"
#include "catalog/pg_type.h"
@@ -5104,6 +5105,32 @@ pg_subscription_ownercheck(Oid sub_oid, Oid roleid)
}
/*
+ * Ownership check for a extended statistics (specified by OID).
+ */
+bool
+pg_statistics_ownercheck(Oid stat_oid, Oid roleid)
+{
+ HeapTuple tuple;
+ Oid ownerId;
+
+ /* Superusers bypass all permission checking. */
+ if (superuser_arg(roleid))
+ return true;
+
+ tuple = SearchSysCache1(STATEXTOID, ObjectIdGetDatum(stat_oid));
+ if (!HeapTupleIsValid(tuple))
+ ereport(ERROR,
+ (errcode(ERRCODE_UNDEFINED_OBJECT),
+ errmsg("statistics with OID %u do not exist",
stat_oid)));
+
+ ownerId = ((Form_pg_statistic_ext) GETSTRUCT(tuple))->staowner;
+
+ ReleaseSysCache(tuple);
+
+ return has_privs_of_role(roleid, ownerId);
+}
+
+/*
* Check whether specified role has CREATEROLE privilege (or is a superuser)
*
* Note: roles do not have owners per se; instead we use this test in
diff --git a/src/backend/catalog/dependency.c b/src/backend/catalog/dependency.c
index fc088b2..ee27cae 100644
--- a/src/backend/catalog/dependency.c
+++ b/src/backend/catalog/dependency.c
@@ -51,6 +51,7 @@
#include "catalog/pg_publication.h"
#include "catalog/pg_publication_rel.h"
#include "catalog/pg_rewrite.h"
+#include "catalog/pg_statistic_ext.h"
#include "catalog/pg_subscription.h"
#include "catalog/pg_tablespace.h"
#include "catalog/pg_transform.h"
@@ -154,6 +155,7 @@ static const Oid object_classes[] = {
RewriteRelationId, /* OCLASS_REWRITE */
TriggerRelationId, /* OCLASS_TRIGGER */
NamespaceRelationId, /* OCLASS_SCHEMA */
+ StatisticExtRelationId, /* OCLASS_STATISTIC_EXT */
TSParserRelationId, /* OCLASS_TSPARSER */
TSDictionaryRelationId, /* OCLASS_TSDICT */
TSTemplateRelationId, /* OCLASS_TSTEMPLATE */
@@ -1263,6 +1265,10 @@ doDeletion(const ObjectAddress *object, int flags)
DropTransformById(object->objectId);
break;
+ case OCLASS_STATISTIC_EXT:
+ RemoveStatisticsById(object->objectId);
+ break;
+
default:
elog(ERROR, "unrecognized object class: %u",
object->classId);
@@ -2377,6 +2383,9 @@ getObjectClass(const ObjectAddress *object)
case NamespaceRelationId:
return OCLASS_SCHEMA;
+ case StatisticExtRelationId:
+ return OCLASS_STATISTIC_EXT;
+
case TSParserRelationId:
return OCLASS_TSPARSER;
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 41c0056..c944b57 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -52,6 +52,7 @@
#include "catalog/pg_opclass.h"
#include "catalog/pg_partitioned_table.h"
#include "catalog/pg_statistic.h"
+#include "catalog/pg_statistic_ext.h"
#include "catalog/pg_tablespace.h"
#include "catalog/pg_type.h"
#include "catalog/pg_type_fn.h"
@@ -1608,7 +1609,10 @@ RemoveAttributeById(Oid relid, AttrNumber attnum)
heap_close(attr_rel, RowExclusiveLock);
if (attnum > 0)
+ {
RemoveStatistics(relid, attnum);
+ RemoveStatisticsExt(relid, attnum);
+ }
relation_close(rel, NoLock);
}
@@ -1856,6 +1860,11 @@ heap_drop_with_catalog(Oid relid)
RemoveStatistics(relid, 0);
/*
+ * delete multi-variate statistics
+ */
+ RemoveStatisticsExt(relid, 0);
+
+ /*
* delete attribute tuples
*/
DeleteAttributeTuples(relid);
@@ -2766,6 +2775,98 @@ RemoveStatistics(Oid relid, AttrNumber attnum)
/*
+ * RemoveStatisticsExt --- remove entries in pg_statistic_ext for a rel
+ *
+ * If attnum is zero, remove all entries for rel; else remove only the one(s)
+ * for that column.
+ */
+void
+RemoveStatisticsExt(Oid relid, AttrNumber attnum)
+{
+ Relation pgstatisticext;
+ TupleDesc tupdesc = NULL;
+ SysScanDesc scan;
+ ScanKeyData key;
+ HeapTuple tuple;
+
+ /*
+ * When dropping a column, we'll drop statistics with a single remaining
+ * (undropped column). To do that, we need the tuple descriptor.
+ *
+ * We already have the relation locked (as we're running ALTER TABLE ...
+ * DROP COLUMN), so we'll just get the descriptor here.
+ */
+ if (attnum != 0)
+ {
+ Relation rel = relation_open(relid, NoLock);
+
+ /* extended stats are supported on tables and matviews */
+ if (rel->rd_rel->relkind == RELKIND_RELATION ||
+ rel->rd_rel->relkind == RELKIND_MATVIEW)
+ tupdesc = RelationGetDescr(rel);
+
+ relation_close(rel, NoLock);
+ }
+
+ if (tupdesc == NULL)
+ return;
+
+ pgstatisticext = heap_open(StatisticExtRelationId, RowExclusiveLock);
+
+ ScanKeyInit(&key,
+ Anum_pg_statistic_ext_starelid,
+ BTEqualStrategyNumber, F_OIDEQ,
+ ObjectIdGetDatum(relid));
+
+ scan = systable_beginscan(pgstatisticext,
+
StatisticExtRelidIndexId,
+ true, NULL, 1, &key);
+
+ /* we must loop even when attnum != 0, in case of inherited stats */
+ while (HeapTupleIsValid(tuple = systable_getnext(scan)))
+ {
+ bool delete = true;
+
+ if (attnum != 0)
+ {
+ Datum adatum;
+ bool isnull;
+ int i;
+ int ncolumns = 0;
+ ArrayType *arr;
+ int16 *attnums;
+
+ /* get the columns */
+ adatum = SysCacheGetAttr(STATEXTOID, tuple,
+
Anum_pg_statistic_ext_stakeys, &isnull);
+ Assert(!isnull);
+
+ arr = DatumGetArrayTypeP(adatum);
+ attnums = (int16 *) ARR_DATA_PTR(arr);
+
+ for (i = 0; i < ARR_DIMS(arr)[0]; i++)
+ {
+ /* count the column unless it's has been / is
being dropped */
+ if ((!tupdesc->attrs[attnums[i] -
1]->attisdropped) &&
+ (attnums[i] != attnum))
+ ncolumns += 1;
+ }
+
+ /* delete if there are less than two attributes */
+ delete = (ncolumns < 2);
+ }
+
+ if (delete)
+ simple_heap_delete(pgstatisticext, &tuple->t_self);
+ }
+
+ systable_endscan(scan);
+
+ heap_close(pgstatisticext, RowExclusiveLock);
+}
+
+
+/*
* RelationTruncateIndexes - truncate all indexes associated
* with the heap relation to zero tuples.
*
diff --git a/src/backend/catalog/namespace.c b/src/backend/catalog/namespace.c
index a38da30..e521bd9 100644
--- a/src/backend/catalog/namespace.c
+++ b/src/backend/catalog/namespace.c
@@ -2086,6 +2086,62 @@ ConversionIsVisible(Oid conid)
}
/*
+ * get_statistics_oid - find a statistics by possibly qualified name
+ *
+ * If not found, returns InvalidOid if missing_ok, else throws error
+ */
+Oid
+get_statistics_oid(List *names, bool missing_ok)
+{
+ char *schemaname;
+ char *stats_name;
+ Oid namespaceId;
+ Oid stats_oid = InvalidOid;
+ ListCell *l;
+
+ /* deconstruct the name list */
+ DeconstructQualifiedName(names, &schemaname, &stats_name);
+
+ if (schemaname)
+ {
+ /* use exact schema given */
+ namespaceId = LookupExplicitNamespace(schemaname, missing_ok);
+ if (missing_ok && !OidIsValid(namespaceId))
+ stats_oid = InvalidOid;
+ else
+ stats_oid = GetSysCacheOid2(STATEXTNAMENSP,
+
PointerGetDatum(stats_name),
+
ObjectIdGetDatum(namespaceId));
+ }
+ else
+ {
+ /* search for it in search path */
+ recomputeNamespacePath();
+
+ foreach(l, activeSearchPath)
+ {
+ namespaceId = lfirst_oid(l);
+
+ if (namespaceId == myTempNamespace)
+ continue; /* do not look in temp
namespace */
+ stats_oid = GetSysCacheOid2(STATEXTNAMENSP,
+
PointerGetDatum(stats_name),
+
ObjectIdGetDatum(namespaceId));
+ if (OidIsValid(stats_oid))
+ break;
+ }
+ }
+
+ if (!OidIsValid(stats_oid) && !missing_ok)
+ ereport(ERROR,
+ (errcode(ERRCODE_UNDEFINED_OBJECT),
+ errmsg("statistics \"%s\" do not exist",
+ NameListToString(names))));
+
+ return stats_oid;
+}
+
+/*
* get_ts_parser_oid - find a TS parser by possibly qualified name
*
* If not found, returns InvalidOid if missing_ok, else throws error
diff --git a/src/backend/catalog/objectaddress.c
b/src/backend/catalog/objectaddress.c
index 3a7f049..a346215 100644
--- a/src/backend/catalog/objectaddress.c
+++ b/src/backend/catalog/objectaddress.c
@@ -48,6 +48,7 @@
#include "catalog/pg_publication.h"
#include "catalog/pg_publication_rel.h"
#include "catalog/pg_rewrite.h"
+#include "catalog/pg_statistic_ext.h"
#include "catalog/pg_subscription.h"
#include "catalog/pg_tablespace.h"
#include "catalog/pg_transform.h"
@@ -478,6 +479,18 @@ static const ObjectPropertyType ObjectProperty[] =
InvalidAttrNumber,
ACL_KIND_SUBSCRIPTION,
true
+ },
+ {
+ StatisticExtRelationId,
+ StatisticExtOidIndexId,
+ STATEXTOID,
+ STATEXTNAMENSP,
+ Anum_pg_statistic_ext_staname,
+ Anum_pg_statistic_ext_stanamespace,
+ Anum_pg_statistic_ext_staowner,
+ InvalidAttrNumber, /* no ACL (same as relation) */
+ -1, /* no ACL */
+ true
}
};
@@ -696,6 +709,10 @@ static const struct object_type_map
/* OCLASS_TRANSFORM */
{
"transform", OBJECT_TRANSFORM
+ },
+ /* OBJECT_STATISTICS */
+ {
+ "statistics", OBJECT_STATISTICS
}
};
@@ -974,6 +991,12 @@ get_object_address(ObjectType objtype, Node *object,
address =
get_object_address_defacl(castNode(List, object),
missing_ok);
break;
+ case OBJECT_STATISTICS:
+ address.classId = StatisticExtRelationId;
+ address.objectId =
get_statistics_oid(castNode(List, object),
+
missing_ok);
+ address.objectSubId = 0;
+ break;
default:
elog(ERROR, "unrecognized objtype: %d", (int)
objtype);
/* placate compiler, in case it thinks elog
might return */
@@ -2079,6 +2102,7 @@ pg_get_object_address(PG_FUNCTION_ARGS)
case OBJECT_ATTRIBUTE:
case OBJECT_COLLATION:
case OBJECT_CONVERSION:
+ case OBJECT_STATISTICS:
case OBJECT_TSPARSER:
case OBJECT_TSDICTIONARY:
case OBJECT_TSTEMPLATE:
@@ -2366,6 +2390,10 @@ check_object_ownership(Oid roleid, ObjectType objtype,
ObjectAddress address,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be superuser")));
break;
+ case OBJECT_STATISTICS:
+ if (!pg_statistics_ownercheck(address.objectId, roleid))
+ aclcheck_error_type(ACLCHECK_NOT_OWNER,
address.objectId);
+ break;
default:
elog(ERROR, "unrecognized object type: %d",
(int) objtype);
@@ -3853,6 +3881,10 @@ getObjectTypeDescription(const ObjectAddress *object)
appendStringInfoString(&buffer, "subscription");
break;
+ case OCLASS_STATISTIC_EXT:
+ appendStringInfoString(&buffer, "extended statistics");
+ break;
+
default:
appendStringInfo(&buffer, "unrecognized %u",
object->classId);
break;
@@ -4876,6 +4908,29 @@ getObjectIdentityParts(const ObjectAddress *object,
break;
}
+ case OCLASS_STATISTIC_EXT:
+ {
+ HeapTuple tup;
+ Form_pg_statistic_ext formStatistic;
+ char *schema;
+
+ tup = SearchSysCache1(STATEXTOID,
+
ObjectIdGetDatum(object->objectId));
+ if (!HeapTupleIsValid(tup))
+ elog(ERROR, "cache lookup failed for
statistics %u",
+ object->objectId);
+ formStatistic = (Form_pg_statistic_ext)
GETSTRUCT(tup);
+ schema =
get_namespace_name_or_temp(formStatistic->stanamespace);
+ appendStringInfoString(&buffer,
+
quote_qualified_identifier(schema,
+
NameStr(formStatistic->staname)));
+ if (objname)
+ *objname = list_make2(schema,
+
pstrdup(NameStr(formStatistic->staname)));
+ ReleaseSysCache(tup);
+ }
+ break;
+
default:
appendStringInfo(&buffer, "unrecognized object %u %u
%d",
object->classId,
diff --git a/src/backend/catalog/system_views.sql
b/src/backend/catalog/system_views.sql
index 0bce209..f3b3578 100644
--- a/src/backend/catalog/system_views.sql
+++ b/src/backend/catalog/system_views.sql
@@ -186,6 +186,16 @@ CREATE OR REPLACE VIEW pg_sequences AS
WHERE NOT pg_is_other_temp_schema(N.oid)
AND relkind = 'S';
+CREATE VIEW pg_stats_ext AS
+ SELECT
+ N.nspname AS schemaname,
+ C.relname AS tablename,
+ S.staname AS staname,
+ S.stakeys AS attnums,
+ length(s.standistinct) AS ndistbytes
+ FROM (pg_statistic_ext S JOIN pg_class C ON (C.oid = S.starelid))
+ LEFT JOIN pg_namespace N ON (N.oid = C.relnamespace);
+
CREATE VIEW pg_stats WITH (security_barrier) AS
SELECT
nspname AS schemaname,
diff --git a/src/backend/commands/Makefile b/src/backend/commands/Makefile
index e0fab38..4a6c99e 100644
--- a/src/backend/commands/Makefile
+++ b/src/backend/commands/Makefile
@@ -18,8 +18,8 @@ OBJS = amcmds.o aggregatecmds.o alter.o analyze.o async.o
cluster.o comment.o \
event_trigger.o explain.o extension.o foreigncmds.o functioncmds.o \
indexcmds.o lockcmds.o matview.o operatorcmds.o opclasscmds.o \
policy.o portalcmds.o prepare.o proclang.o publicationcmds.o \
- schemacmds.o seclabel.o sequence.o subscriptioncmds.o tablecmds.o \
- tablespace.o trigger.o tsearchcmds.o typecmds.o user.o vacuum.o \
- vacuumlazy.o variable.o view.o
+ schemacmds.o seclabel.o sequence.o statscmds.o subscriptioncmds.o \
+ tablecmds.o tablespace.o trigger.o tsearchcmds.o typecmds.o user.o \
+ vacuum.o vacuumlazy.o variable.o view.o
include $(top_srcdir)/src/backend/common.mk
diff --git a/src/backend/commands/alter.c b/src/backend/commands/alter.c
index cf1391c..bf1aba1 100644
--- a/src/backend/commands/alter.c
+++ b/src/backend/commands/alter.c
@@ -373,6 +373,7 @@ ExecRenameStmt(RenameStmt *stmt)
case OBJECT_OPCLASS:
case OBJECT_OPFAMILY:
case OBJECT_LANGUAGE:
+ case OBJECT_STATISTICS:
case OBJECT_TSCONFIGURATION:
case OBJECT_TSDICTIONARY:
case OBJECT_TSPARSER:
@@ -489,6 +490,7 @@ ExecAlterObjectSchemaStmt(AlterObjectSchemaStmt *stmt,
case OBJECT_OPERATOR:
case OBJECT_OPCLASS:
case OBJECT_OPFAMILY:
+ case OBJECT_STATISTICS:
case OBJECT_TSCONFIGURATION:
case OBJECT_TSDICTIONARY:
case OBJECT_TSPARSER:
@@ -803,6 +805,7 @@ ExecAlterOwnerStmt(AlterOwnerStmt *stmt)
case OBJECT_OPERATOR:
case OBJECT_OPCLASS:
case OBJECT_OPFAMILY:
+ case OBJECT_STATISTICS:
case OBJECT_TABLESPACE:
case OBJECT_TSDICTIONARY:
case OBJECT_TSCONFIGURATION:
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index b91df98..39d9bdb 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -17,6 +17,7 @@
#include <math.h>
#include "access/multixact.h"
+#include "access/sysattr.h"
#include "access/transam.h"
#include "access/tupconvert.h"
#include "access/tuptoaster.h"
@@ -28,6 +29,7 @@
#include "catalog/pg_collation.h"
#include "catalog/pg_inherits_fn.h"
#include "catalog/pg_namespace.h"
+#include "catalog/pg_statistic_ext.h"
#include "commands/dbcommands.h"
#include "commands/tablecmds.h"
#include "commands/vacuum.h"
@@ -39,13 +41,17 @@
#include "parser/parse_relation.h"
#include "pgstat.h"
#include "postmaster/autovacuum.h"
+#include "statistics/common.h"
+#include "statistics/stats.h"
#include "storage/bufmgr.h"
#include "storage/lmgr.h"
#include "storage/proc.h"
#include "storage/procarray.h"
#include "utils/acl.h"
#include "utils/attoptcache.h"
+#include "utils/builtins.h"
#include "utils/datum.h"
+#include "utils/fmgroids.h"
#include "utils/guc.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
@@ -566,6 +572,9 @@ do_analyze_rel(Relation onerel, int options, VacuumParams
*params,
update_attstats(RelationGetRelid(Irel[ind]), false,
thisdata->attr_cnt,
thisdata->vacattrstats);
}
+
+ /* Build extended statistics (if there are any). */
+ build_ext_stats(onerel, totalrows, numrows, rows, attr_cnt,
vacattrstats);
}
/*
@@ -1683,19 +1692,6 @@ ind_fetch_func(VacAttrStatsP stats, int rownum, bool
*isNull)
*/
typedef struct
{
- Oid eqopr; /* '=' operator for
datatype, if any */
- Oid eqfunc; /* and associated
function */
- Oid ltopr; /* '<' operator for
datatype, if any */
-} StdAnalyzeData;
-
-typedef struct
-{
- Datum value; /* a data value */
- int tupno; /* position index for
tuple it came from */
-} ScalarItem;
-
-typedef struct
-{
int count; /* # of duplicates */
int first; /* values[] index of
first occurrence */
} ScalarMCVItem;
diff --git a/src/backend/commands/dropcmds.c b/src/backend/commands/dropcmds.c
index ab73fbf..e7ae4a5 100644
--- a/src/backend/commands/dropcmds.c
+++ b/src/backend/commands/dropcmds.c
@@ -286,6 +286,13 @@ does_not_exist_skipping(ObjectType objtype, Node *object)
msg = gettext_noop("schema \"%s\" does not exist,
skipping");
name = strVal((Value *) object);
break;
+ case OBJECT_STATISTICS:
+ if (!schema_does_not_exist_skipping(castNode(List,
object), &msg, &name))
+ {
+ msg = gettext_noop("statistics \"%s\" do not
exist, skipping");
+ name = NameListToString(castNode(List, object));
+ }
+ break;
case OBJECT_TSPARSER:
if (!schema_does_not_exist_skipping(castNode(List,
object), &msg, &name))
{
diff --git a/src/backend/commands/event_trigger.c
b/src/backend/commands/event_trigger.c
index 346b347..b84a10f 100644
--- a/src/backend/commands/event_trigger.c
+++ b/src/backend/commands/event_trigger.c
@@ -112,6 +112,7 @@ static event_trigger_support_data event_trigger_support[] =
{
{"SCHEMA", true},
{"SEQUENCE", true},
{"SERVER", true},
+ {"STATISTICS", true},
{"SUBSCRIPTION", true},
{"TABLE", true},
{"TABLESPACE", false},
@@ -1108,6 +1109,7 @@ EventTriggerSupportsObjectType(ObjectType obtype)
case OBJECT_SCHEMA:
case OBJECT_SEQUENCE:
case OBJECT_SUBSCRIPTION:
+ case OBJECT_STATISTICS:
case OBJECT_TABCONSTRAINT:
case OBJECT_TABLE:
case OBJECT_TRANSFORM:
@@ -1173,6 +1175,7 @@ EventTriggerSupportsObjectClass(ObjectClass objclass)
case OCLASS_PUBLICATION:
case OCLASS_PUBLICATION_REL:
case OCLASS_SUBSCRIPTION:
+ case OCLASS_STATISTIC_EXT:
return true;
}
diff --git a/src/backend/commands/statscmds.c b/src/backend/commands/statscmds.c
new file mode 100644
index 0000000..77d7a36
--- /dev/null
+++ b/src/backend/commands/statscmds.c
@@ -0,0 +1,270 @@
+/*-------------------------------------------------------------------------
+ *
+ * statscmds.c
+ * Commands for creating and altering extended statistics
+ *
+ * Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ * src/backend/commands/statscmds.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "access/relscan.h"
+#include "catalog/dependency.h"
+#include "catalog/indexing.h"
+#include "catalog/namespace.h"
+#include "catalog/pg_namespace.h"
+#include "catalog/pg_statistic_ext.h"
+#include "commands/defrem.h"
+#include "miscadmin.h"
+#include "statistics/stats.h"
+#include "utils/builtins.h"
+#include "utils/inval.h"
+#include "utils/memutils.h"
+#include "utils/rel.h"
+#include "utils/syscache.h"
+
+
+/* used for sorting the attnums in ExecCreateStatistics */
+static int
+compare_int16(const void *a, const void *b)
+{
+ return memcmp(a, b, sizeof(int16));
+}
+
+/*
+ * Implements the CREATE STATISTICS name ON (columns) FROM table
+ *
+ * We do require that the types support sorting (ltopr), although some
+ * statistics might work with equality only.
+ */
+ObjectAddress
+CreateStatistics(CreateStatsStmt *stmt)
+{
+ int i;
+ ListCell *l;
+ int16 attnums[STATS_MAX_DIMENSIONS];
+ int numcols = 0;
+ ObjectAddress address = InvalidObjectAddress;
+ char *namestr;
+ NameData staname;
+ Oid statoid;
+ Oid namespaceId;
+
+ HeapTuple htup;
+ Datum values[Natts_pg_statistic_ext];
+ bool nulls[Natts_pg_statistic_ext];
+ int2vector *stakeys;
+ Relation statrel;
+ Relation rel;
+ Oid relid;
+ ObjectAddress parentobject,
+ childobject;
+
+ /* costruction of array of enabled statistic */
+ Datum types[1]; /* only ndistinct defined now */
+ int ntypes;
+ ArrayType *staenabled;
+
+ Assert(IsA(stmt, CreateStatsStmt));
+
+ /* resolve the pieces of the name (namespace etc.) */
+ namespaceId = QualifiedNameGetCreationNamespace(stmt->defnames,
&namestr);
+ namestrcpy(&staname, namestr);
+
+ /*
+ * If if_not_exists was given and the statistics already exists, bail
out.
+ */
+ if (SearchSysCacheExists2(STATEXTNAMENSP,
+
PointerGetDatum(&staname),
+
ObjectIdGetDatum(namespaceId)))
+ {
+ if (stmt->if_not_exists)
+ {
+ ereport(NOTICE,
+ (errcode(ERRCODE_DUPLICATE_OBJECT),
+ errmsg("statistics \"%s\" already
exist, skipping",
+ namestr)));
+ return InvalidObjectAddress;
+ }
+
+ ereport(ERROR,
+ (errcode(ERRCODE_DUPLICATE_OBJECT),
+ errmsg("statistics \"%s\" already exist",
namestr)));
+ }
+
+ rel = heap_openrv(stmt->relation, AccessExclusiveLock);
+ relid = RelationGetRelid(rel);
+
+ /* ndistinct coefficients is the only known type of extended statistics
*/
+ ntypes = 1;
+ types[0] = CharGetDatum(STATS_EXT_NDISTINCT);
+
+ /*
+ * Transform column names to array of attnums. While doing that, we also
+ * enforce the maximum number of keys.
+ */
+ foreach(l, stmt->keys)
+ {
+ char *attname = strVal(lfirst(l));
+ HeapTuple atttuple;
+
+ atttuple = SearchSysCacheAttName(relid, attname);
+
+ if (!HeapTupleIsValid(atttuple))
+ ereport(ERROR,
+ (errcode(ERRCODE_UNDEFINED_COLUMN),
+ errmsg("column \"%s\" referenced in statistics does
not exist",
+ attname)));
+
+ /* more than STATS_MAX_DIMENSIONS columns not allowed */
+ if (numcols >= STATS_MAX_DIMENSIONS)
+ ereport(ERROR,
+ (errcode(ERRCODE_TOO_MANY_COLUMNS),
+ errmsg("cannot have more than %d keys
in statistics",
+ STATS_MAX_DIMENSIONS)));
+
+ attnums[numcols] = ((Form_pg_attribute)
GETSTRUCT(atttuple))->attnum;
+ ReleaseSysCache(atttuple);
+ numcols++;
+ }
+
+ /*
+ * Check that at least two columns were specified in the statement. The
+ * upper bound was already checked in the loop above.
+ */
+ if (numcols < 2)
+ ereport(ERROR,
+ (errcode(ERRCODE_TOO_MANY_COLUMNS),
+ errmsg("statistics require at least 2
columns")));
+
+ /*
+ * Sort the attnums, which makes detecting duplicies somewhat easier,
and
+ * it does not hurt (it does not affect the efficiency, unlike for
+ * indexes, for example).
+ */
+ qsort(attnums, numcols, sizeof(int16), compare_int16);
+
+ /*
+ * Look for duplicities in the list of columns. The attnums are sorted
so
+ * just check consecutive elements.
+ */
+ for (i = 1; i < numcols; i++)
+ if (attnums[i] == attnums[i - 1])
+ ereport(ERROR,
+ (errcode(ERRCODE_UNDEFINED_COLUMN),
+ errmsg("duplicate column name in statistics
definition")));
+
+ stakeys = buildint2vector(attnums, numcols);
+
+ /* construct the char array of enabled statistic types */
+ staenabled = construct_array(types, ntypes, CHAROID, 1, true, 'c');
+
+ /*
+ * Everything seems fine, so let's build the pg_statistic_ext entry. At
+ * this point we obviously only have the keys and options.
+ */
+
+ memset(values, 0, sizeof(values));
+ memset(nulls, false, sizeof(nulls));
+
+ /* metadata */
+ values[Anum_pg_statistic_ext_starelid - 1] = ObjectIdGetDatum(relid);
+ values[Anum_pg_statistic_ext_staname - 1] = NameGetDatum(&staname);
+ values[Anum_pg_statistic_ext_stanamespace - 1] =
ObjectIdGetDatum(namespaceId);
+ values[Anum_pg_statistic_ext_staowner - 1] =
ObjectIdGetDatum(GetUserId());
+
+ values[Anum_pg_statistic_ext_stakeys - 1] = PointerGetDatum(stakeys);
+
+ /* enabled statistics */
+ values[Anum_pg_statistic_ext_staenabled - 1] =
PointerGetDatum(staenabled);
+
+ /* no statistics build yet */
+ nulls[Anum_pg_statistic_ext_standistinct - 1] = true;
+
+ /* insert the tuple into pg_statistic_ext */
+ statrel = heap_open(StatisticExtRelationId, RowExclusiveLock);
+
+ htup = heap_form_tuple(statrel->rd_att, values, nulls);
+
+ CatalogTupleInsert(statrel, htup);
+
+ statoid = HeapTupleGetOid(htup);
+
+ heap_freetuple(htup);
+
+ /*
+ * Add a dependency on a table, so that stats get dropped on DROP TABLE.
+ */
+ ObjectAddressSet(parentobject, RelationRelationId, relid);
+ ObjectAddressSet(childobject, StatisticExtRelationId, statoid);
+
+ recordDependencyOn(&childobject, &parentobject, DEPENDENCY_AUTO);
+
+ /*
+ * Also add dependency on the schema (to drop statistics on DROP
SCHEMA).
+ * This is not handled automatically by DROP TABLE because statistics
have
+ * their own schema.
+ */
+ ObjectAddressSet(parentobject, NamespaceRelationId, namespaceId);
+
+ recordDependencyOn(&childobject, &parentobject, DEPENDENCY_AUTO);
+
+ heap_close(statrel, RowExclusiveLock);
+
+ relation_close(rel, NoLock);
+
+ /*
+ * Invalidate relcache so that others see the new statistics.
+ */
+ CacheInvalidateRelcache(rel);
+
+ ObjectAddressSet(address, StatisticExtRelationId, statoid);
+
+ return address;
+}
+
+
+/*
+ * Implements the DROP STATISTICS
+ *
+ * DROP STATISTICS stats_name
+ */
+void
+RemoveStatisticsById(Oid statsOid)
+{
+ Relation relation;
+ Oid relid;
+ Relation rel;
+ HeapTuple tup;
+ Form_pg_statistic_ext statext;
+
+ /*
+ * Delete the pg_proc tuple.
+ */
+ relation = heap_open(StatisticExtRelationId, RowExclusiveLock);
+
+ tup = SearchSysCache1(STATEXTOID, ObjectIdGetDatum(statsOid));
+
+ if (!HeapTupleIsValid(tup)) /* should not happen */
+ elog(ERROR, "cache lookup failed for statistics %u", statsOid);
+
+ statext = (Form_pg_statistic_ext) GETSTRUCT(tup);
+ relid = statext->starelid;
+
+ rel = heap_open(relid, AccessExclusiveLock);
+
+ simple_heap_delete(relation, &tup->t_self);
+
+ CacheInvalidateRelcache(rel);
+
+ ReleaseSysCache(tup);
+
+ heap_close(relation, RowExclusiveLock);
+ heap_close(rel, NoLock);
+}
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index bfc2ac1..9a34f94 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -4447,6 +4447,19 @@ _copyDropSubscriptionStmt(const DropSubscriptionStmt
*from)
return newnode;
}
+static CreateStatsStmt *
+_copyCreateStatsStmt(const CreateStatsStmt *from)
+{
+ CreateStatsStmt *newnode = makeNode(CreateStatsStmt);
+
+ COPY_NODE_FIELD(defnames);
+ COPY_NODE_FIELD(relation);
+ COPY_NODE_FIELD(keys);
+ COPY_SCALAR_FIELD(if_not_exists);
+
+ return newnode;
+}
+
/* ****************************************************************
* pg_list.h copy functions
* ****************************************************************
@@ -5385,6 +5398,9 @@ copyObject(const void *from)
case T_CommonTableExpr:
retval = _copyCommonTableExpr(from);
break;
+ case T_CreateStatsStmt:
+ retval = _copyCreateStatsStmt(from);
+ break;
case T_ObjectWithArgs:
retval = _copyObjectWithArgs(from);
break;
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 7418fbe..953e6e2 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -2266,6 +2266,18 @@ _outForeignKeyOptInfo(StringInfo str, const
ForeignKeyOptInfo *node)
}
static void
+_outStatisticExtInfo(StringInfo str, const StatisticExtInfo *node)
+{
+ WRITE_NODE_TYPE("STATISTICEXTINFO");
+
+ /* NB: this isn't a complete set of fields */
+ WRITE_OID_FIELD(statOid);
+
+ /* built/available statistics */
+ WRITE_BOOL_FIELD(ndist_built);
+}
+
+static void
_outEquivalenceClass(StringInfo str, const EquivalenceClass *node)
{
/*
@@ -3915,6 +3927,9 @@ outNode(StringInfo str, const void *obj)
case T_PlannerParamItem:
_outPlannerParamItem(str, obj);
break;
+ case T_StatisticExtInfo:
+ _outStatisticExtInfo(str, obj);
+ break;
case T_ExtensibleNode:
_outExtensibleNode(str, obj);
diff --git a/src/backend/optimizer/util/plancat.c
b/src/backend/optimizer/util/plancat.c
index 463f806..d90f199 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -29,6 +29,7 @@
#include "catalog/heap.h"
#include "catalog/partition.h"
#include "catalog/pg_am.h"
+#include "catalog/pg_statistic_ext.h"
#include "foreign/fdwapi.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
@@ -40,8 +41,11 @@
#include "parser/parse_relation.h"
#include "parser/parsetree.h"
#include "rewrite/rewriteManip.h"
+#include "statistics/stats.h"
#include "storage/bufmgr.h"
+#include "utils/builtins.h"
#include "utils/lsyscache.h"
+#include "utils/syscache.h"
#include "utils/rel.h"
#include "utils/snapmgr.h"
@@ -63,7 +67,7 @@ static List *get_relation_constraints(PlannerInfo *root,
bool include_notnull);
static List *build_index_tlist(PlannerInfo *root, IndexOptInfo *index,
Relation heapRelation);
-
+static List *get_relation_statistics(RelOptInfo *rel, Relation relation);
/*
* get_relation_info -
@@ -398,6 +402,8 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId,
bool inhparent,
rel->indexlist = indexinfos;
+ rel->statlist = get_relation_statistics(rel, relation);
+
/* Grab foreign-table info using the relcache, while we have it */
if (relation->rd_rel->relkind == RELKIND_FOREIGN_TABLE)
{
@@ -1251,6 +1257,64 @@ get_relation_constraints(PlannerInfo *root,
return result;
}
+/*
+ * get_relation_statistics
+ *
+ * Retrieve extended statistics defined on the table.
+ *
+ * Returns a List (possibly empty) of StatisticExtInfo objects describing
+ * the statistics. Only attributes needed for selecting statistics are
+ * retrieved (columns covered by the statistics, etc.).
+ */
+static List *
+get_relation_statistics(RelOptInfo *rel, Relation relation)
+{
+ List *statoidlist;
+ ListCell *l;
+ List *stainfos = NIL;
+
+ statoidlist = RelationGetStatExtList(relation);
+
+ foreach(l, statoidlist)
+ {
+ ArrayType *arr;
+ Datum adatum;
+ bool isnull;
+ Oid statOid = lfirst_oid(l);
+
+ HeapTuple htup = SearchSysCache1(STATEXTOID,
ObjectIdGetDatum(statOid));
+
+ /* unavailable stats are not interesting for the planner */
+ if (stats_are_built(htup, STATS_EXT_NDISTINCT))
+ {
+ StatisticExtInfo *info = makeNode(StatisticExtInfo);
+
+ info->statOid = statOid;
+ info->rel = rel;
+
+ /* built/available statistics */
+ info->ndist_built = true;
+
+ /* decode the stakeys array */
+ adatum = SysCacheGetAttr(STATEXTOID, htup,
+
Anum_pg_statistic_ext_stakeys, &isnull);
+ Assert(!isnull);
+
+ arr = DatumGetArrayTypeP(adatum);
+
+ info->stakeys = buildint2vector((int16 *)
ARR_DATA_PTR(arr),
+
ARR_DIMS(arr)[0]);
+
+ stainfos = lcons(info, stainfos);
+ }
+
+ ReleaseSysCache(htup);
+ }
+
+ list_free(statoidlist);
+
+ return stainfos;
+}
/*
* relation_excluded_by_constraints
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index e7acc2d..a0801dc 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -257,7 +257,7 @@ static Node *makeRecursiveViewSelect(char *relname, List
*aliases, Node *query);
ConstraintsSetStmt CopyStmt CreateAsStmt CreateCastStmt
CreateDomainStmt CreateExtensionStmt CreateGroupStmt
CreateOpClassStmt
CreateOpFamilyStmt AlterOpFamilyStmt CreatePLangStmt
- CreateSchemaStmt CreateSeqStmt CreateStmt CreateTableSpaceStmt
+ CreateSchemaStmt CreateSeqStmt CreateStmt CreateStatsStmt
CreateTableSpaceStmt
CreateFdwStmt CreateForeignServerStmt CreateForeignTableStmt
CreateAssertStmt CreateTransformStmt CreateTrigStmt
CreateEventTrigStmt
CreateUserStmt CreateUserMappingStmt CreateRoleStmt
CreatePolicyStmt
@@ -873,6 +873,7 @@ stmt :
| CreateSeqStmt
| CreateStmt
| CreateSubscriptionStmt
+ | CreateStatsStmt
| CreateTableSpaceStmt
| CreateTransformStmt
| CreateTrigStmt
@@ -3746,6 +3747,34 @@ OptConsTableSpace: USING INDEX TABLESPACE name { $$ =
$4; }
ExistingIndex: USING INDEX index_name { $$ =
$3; }
;
+/*****************************************************************************
+ *
+ * QUERY :
+ * CREATE STATISTICS stats_name ON relname
(columns) WITH (options)
+ *
+ *****************************************************************************/
+
+
+CreateStatsStmt: CREATE STATISTICS any_name ON '(' columnList ')' FROM
qualified_name
+ {
+ CreateStatsStmt *n =
makeNode(CreateStatsStmt);
+ n->defnames = $3;
+ n->relation = $9;
+ n->keys = $6;
+ n->if_not_exists =
false;
+ $$ = (Node *)n;
+ }
+ | CREATE STATISTICS IF_P NOT EXISTS
any_name ON '(' columnList ')' FROM qualified_name
+ {
+ CreateStatsStmt *n =
makeNode(CreateStatsStmt);
+ n->defnames = $6;
+ n->relation = $12;
+ n->keys = $9;
+ n->if_not_exists = true;
+ $$ = (Node *)n;
+ }
+ ;
+
/*****************************************************************************
*
@@ -6033,6 +6062,7 @@ drop_type_name:
| PUBLICATION
{ $$ = OBJECT_PUBLICATION; }
| SCHEMA
{ $$ = OBJECT_SCHEMA; }
| SERVER
{ $$ = OBJECT_FOREIGN_SERVER; }
+ | STATISTICS
{ $$ = OBJECT_STATISTICS; }
;
/* object types attached to a table */
@@ -8377,6 +8407,15 @@ RenameStmt: ALTER AGGREGATE aggregate_with_argtypes
RENAME TO name
n->missing_ok = false;
$$ = (Node *)n;
}
+ | ALTER STATISTICS any_name RENAME TO name
+ {
+ RenameStmt *n = makeNode(RenameStmt);
+ n->renameType = OBJECT_STATISTICS;
+ n->object = (Node *) $3;
+ n->newname = $6;
+ n->missing_ok = false;
+ $$ = (Node *)n;
+ }
| ALTER TEXT_P SEARCH PARSER any_name RENAME TO name
{
RenameStmt *n = makeNode(RenameStmt);
@@ -8592,6 +8631,15 @@ AlterObjectSchemaStmt:
n->missing_ok = true;
$$ = (Node *)n;
}
+ | ALTER STATISTICS any_name SET SCHEMA name
+ {
+ AlterObjectSchemaStmt *n =
makeNode(AlterObjectSchemaStmt);
+ n->objectType = OBJECT_STATISTICS;
+ n->object = (Node *) $3;
+ n->newschema = $6;
+ n->missing_ok = false;
+ $$ = (Node *)n;
+ }
| ALTER TEXT_P SEARCH PARSER any_name SET SCHEMA name
{
AlterObjectSchemaStmt *n =
makeNode(AlterObjectSchemaStmt);
@@ -8855,6 +8903,14 @@ AlterOwnerStmt: ALTER AGGREGATE aggregate_with_argtypes
OWNER TO RoleSpec
n->newowner = $6;
$$ = (Node *)n;
}
+ | ALTER STATISTICS name OWNER TO RoleSpec
+ {
+ AlterOwnerStmt *n =
makeNode(AlterOwnerStmt);
+ n->objectType = OBJECT_STATISTICS;
+ n->object = (Node *) makeString($3);
+ n->newowner = $6;
+ $$ = (Node *)n;
+ }
| ALTER TEXT_P SEARCH DICTIONARY any_name OWNER TO
RoleSpec
{
AlterOwnerStmt *n =
makeNode(AlterOwnerStmt);
diff --git a/src/backend/statistics/Makefile b/src/backend/statistics/Makefile
new file mode 100644
index 0000000..e77b350
--- /dev/null
+++ b/src/backend/statistics/Makefile
@@ -0,0 +1,17 @@
+#-------------------------------------------------------------------------
+#
+# Makefile--
+# Makefile for statistics
+#
+# IDENTIFICATION
+# src/backend/statistics/Makefile
+#
+#-------------------------------------------------------------------------
+
+subdir = src/backend/statistics
+top_builddir = ../../..
+include $(top_builddir)/src/Makefile.global
+
+OBJS = common.o mvdist.o
+
+include $(top_srcdir)/src/backend/common.mk
diff --git a/src/backend/statistics/README b/src/backend/statistics/README
new file mode 100644
index 0000000..beb7c24
--- /dev/null
+++ b/src/backend/statistics/README
@@ -0,0 +1,34 @@
+Extended statistics
+===================
+
+When estimating various quantities (e.g. condition selectivities) the default
+approach relies on the assumption of independence. In practice that's often
+not true, resulting in estimation errors.
+
+Extended statistics track different types of dependencies between the columns,
+hopefully improving the estimates and producing better plans.
+
+Currently we only have one type of extended statistics - ndistinct
+coefficients, and we use it to improve estimates of grouping queries. See
+README.ndistinct for details.
+
+
+Size of sample in ANALYZE
+-------------------------
+When performing ANALYZE, the number of rows to sample is determined as
+
+ (300 * statistics_target)
+
+That works reasonably well for statistics on individual columns, but perhaps
+it's not enough for extended statistics. Papers analyzing estimation errors
+all use samples proportional to the table (usually finding that 1-3% of the
+table is enough to build accurate stats).
+
+The requested accuracy (number of MCV items or histogram bins) should also
+be considered when determining the sample size, and in extended statistics
+those are not necessarily limited by statistics_target.
+
+This however merits further discussion, because collecting the sample is quite
+expensive and increasing it further would make ANALYZE even more painful.
+Judging by the experiments with the current implementation, the fixed size
+seems to work reasonably well for now, so we leave this as a future work.
diff --git a/src/backend/statistics/README.ndistinct
b/src/backend/statistics/README.ndistinct
new file mode 100644
index 0000000..9365b17
--- /dev/null
+++ b/src/backend/statistics/README.ndistinct
@@ -0,0 +1,22 @@
+ndistinct coefficients
+======================
+
+Estimating number of groups in a combination of columns (e.g. for GROUP BY)
+is tricky, and the estimation error is often significant.
+
+The ndistinct coefficients address this by storing ndistinct estimates not
+only for individual columns, but also for (all) combinations of columns.
+So for example given three columns (a,b,c) the statistics will estimate
+ndistinct for (a,b), (a,c), (b,c) and (a,b,c). The per-column estimates
+are already available in pg_statistic.
+
+
+GROUP BY estimation (estimate_num_groups)
+-----------------------------------------
+
+Although ndistinct coefficient might be used for selectivity estimation
+(of equality conditions in WHERE clause), that is not implemented at this
+point.
+
+Instead, ndistinct coefficients are only used in estimate_num_groups() to
+estimate grouped queries.
diff --git a/src/backend/statistics/common.c b/src/backend/statistics/common.c
new file mode 100644
index 0000000..f63d8cc
--- /dev/null
+++ b/src/backend/statistics/common.c
@@ -0,0 +1,454 @@
+/*-------------------------------------------------------------------------
+ *
+ * common.c
+ * POSTGRES extended statistics
+ *
+ *
+ * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ * src/backend/statistics/common.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "access/genam.h"
+#include "access/heapam.h"
+#include "access/htup_details.h"
+#include "catalog/indexing.h"
+#include "catalog/pg_collation.h"
+#include "catalog/pg_statistic_ext.h"
+#include "nodes/relation.h"
+#include "statistics/common.h"
+#include "statistics/stats.h"
+#include "utils/builtins.h"
+#include "utils/fmgroids.h"
+#include "utils/rel.h"
+#include "utils/syscache.h"
+
+
+static VacAttrStats **lookup_var_attr_stats(int2vector *attrs,
+ int natts, VacAttrStats
**vacattrstats);
+
+static List *list_ext_stats(Oid relid);
+
+static void update_ext_stats(Oid relid, MVNDistinct ndistinct,
+ int2vector *attrs, VacAttrStats **stats);
+
+
+/*
+ * Compute requested extended stats, using the rows sampled for the plain
+ * (single-column) stats.
+ *
+ * This fetches a list of stats from pg_statistic_ext, computes the stats
+ * and serializes them back into the catalog (as bytea values).
+ */
+void
+build_ext_stats(Relation onerel, double totalrows,
+ int numrows, HeapTuple *rows,
+ int natts, VacAttrStats **vacattrstats)
+{
+ ListCell *lc;
+ List *stats;
+
+ TupleDesc tupdesc = RelationGetDescr(onerel);
+
+ /* Fetch defined statistics from pg_statistic_ext, and compute them. */
+ stats = list_ext_stats(RelationGetRelid(onerel));
+
+ foreach(lc, stats)
+ {
+ int j;
+ StatisticExtInfo *stat = (StatisticExtInfo *) lfirst(lc);
+ MVNDistinct ndistinct = NULL;
+
+ VacAttrStats **stats = NULL;
+ int numatts = 0;
+
+ /* int2 vector of attnums the stats should be computed on */
+ int2vector *attrs = stat->stakeys;
+
+ /* see how many of the columns are not dropped */
+ for (j = 0; j < attrs->dim1; j++)
+ if (!tupdesc->attrs[attrs->values[j] - 1]->attisdropped)
+ numatts += 1;
+
+ /* if there are dropped attributes, build a filtered int2vector
*/
+ if (numatts != attrs->dim1)
+ {
+ int16 *tmp = palloc0(numatts * sizeof(int16));
+ int attnum = 0;
+
+ for (j = 0; j < attrs->dim1; j++)
+ if (!tupdesc->attrs[attrs->values[j] -
1]->attisdropped)
+ tmp[attnum++] = attrs->values[j];
+
+ pfree(attrs);
+ attrs = buildint2vector(tmp, numatts);
+ }
+
+ /* filter only the interesting vacattrstats records */
+ stats = lookup_var_attr_stats(attrs, natts, vacattrstats);
+
+ /* check allowed number of dimensions */
+ Assert((attrs->dim1 >= 2) && (attrs->dim1 <=
STATS_MAX_DIMENSIONS));
+
+ /* compute ndistinct coefficients */
+ if (stat->ndist_enabled)
+ ndistinct = build_ext_ndistinct(totalrows, numrows,
rows, attrs, stats);
+
+ /* store the statistics in the catalog */
+ update_ext_stats(stat->statOid, ndistinct, attrs, stats);
+ }
+}
+
+/*
+ * Lookup the VacAttrStats info for the selected columns, with indexes
+ * matching the attrs vector (to make it easy to work with when
+ * computing extended stats).
+ */
+static VacAttrStats **
+lookup_var_attr_stats(int2vector *attrs, int natts, VacAttrStats
**vacattrstats)
+{
+ int i,
+ j;
+ int numattrs = attrs->dim1;
+ VacAttrStats **stats = (VacAttrStats **) palloc0(numattrs *
sizeof(VacAttrStats *));
+
+ /* lookup VacAttrStats info for the requested columns (same attnum) */
+ for (i = 0; i < numattrs; i++)
+ {
+ stats[i] = NULL;
+ for (j = 0; j < natts; j++)
+ {
+ if (attrs->values[i] == vacattrstats[j]->tupattnum)
+ {
+ stats[i] = vacattrstats[j];
+ break;
+ }
+ }
+
+ /*
+ * Check that we found the info, that the attnum matches and
that
+ * there's the requested 'lt' operator and that the type is
+ * 'passed-by-value'.
+ */
+ Assert(stats[i] != NULL);
+ Assert(stats[i]->tupattnum == attrs->values[i]);
+
+ /*
+ * FIXME This is rather ugly way to check for 'ltopr' (which is
+ * defined for 'scalar' attributes).
+ */
+ Assert(((StdAnalyzeData *) stats[i]->extra_data)->ltopr !=
InvalidOid);
+ }
+
+ return stats;
+}
+
+/*
+ * Fetch list of MV stats defined on a table, without the actual data
+ * for histograms, MCV lists etc.
+ */
+static List *
+list_ext_stats(Oid relid)
+{
+ Relation indrel;
+ SysScanDesc indscan;
+ ScanKeyData skey;
+ HeapTuple htup;
+ List *result = NIL;
+
+ /*
+ * Prepare to scan pg_statistic_ext for entries having indrelid = this
+ * rel.
+ */
+ ScanKeyInit(&skey,
+ Anum_pg_statistic_ext_starelid,
+ BTEqualStrategyNumber, F_OIDEQ,
+ ObjectIdGetDatum(relid));
+
+ indrel = heap_open(StatisticExtRelationId, AccessShareLock);
+ indscan = systable_beginscan(indrel, StatisticExtRelidIndexId, true,
+ NULL, 1,
&skey);
+
+ while (HeapTupleIsValid(htup = systable_getnext(indscan)))
+ {
+ StatisticExtInfo *info = makeNode(StatisticExtInfo);
+ Form_pg_statistic_ext stats = (Form_pg_statistic_ext)
GETSTRUCT(htup);
+
+ info->statOid = HeapTupleGetOid(htup);
+ info->stakeys = buildint2vector(stats->stakeys.values,
stats->stakeys.dim1);
+
+ info->ndist_enabled = stats_are_enabled(htup,
STATS_EXT_NDISTINCT);
+ info->ndist_built = stats_are_built(htup, STATS_EXT_NDISTINCT);
+
+ result = lappend(result, info);
+ }
+
+ systable_endscan(indscan);
+
+ heap_close(indrel, AccessShareLock);
+
+ /*
+ * TODO maybe save the list into relcache, as in RelationGetIndexList
+ * (which was used as an inspiration of this one)?.
+ */
+
+ return result;
+}
+
+/*
+ * update_ext_stats
+ * Serializes the statistics and stores them into the pg_statistic_ext
tuple.
+ */
+static void
+update_ext_stats(Oid statOid, MVNDistinct ndistinct,
+ int2vector *attrs, VacAttrStats **stats)
+{
+ HeapTuple stup,
+ oldtup;
+ Datum values[Natts_pg_statistic_ext];
+ bool nulls[Natts_pg_statistic_ext];
+ bool replaces[Natts_pg_statistic_ext];
+
+ Relation sd = heap_open(StatisticExtRelationId,
RowExclusiveLock);
+
+ memset(nulls, 1, Natts_pg_statistic_ext * sizeof(bool));
+ memset(replaces, 0, Natts_pg_statistic_ext * sizeof(bool));
+ memset(values, 0, Natts_pg_statistic_ext * sizeof(Datum));
+
+ /*
+ * Construct a new pg_statistic_ext tuple - replace only the histogram
and
+ * MCV list, depending whether it actually was computed.
+ */
+ if (ndistinct != NULL)
+ {
+ bytea *data = serialize_ext_ndistinct(ndistinct);
+
+ nulls[Anum_pg_statistic_ext_standistinct - 1] = (data == NULL);
+ values[Anum_pg_statistic_ext_standistinct - 1] =
PointerGetDatum(data);
+ }
+
+ /* always replace the value (either by bytea or NULL) */
+ replaces[Anum_pg_statistic_ext_standistinct - 1] = true;
+
+ /* always change the availability flags */
+ nulls[Anum_pg_statistic_ext_stakeys - 1] = false;
+
+ /* use the new attnums, in case we removed some dropped ones */
+ replaces[Anum_pg_statistic_ext_stakeys - 1] = true;
+
+ values[Anum_pg_statistic_ext_stakeys - 1] = PointerGetDatum(attrs);
+
+ /* Is there already a pg_statistic_ext tuple for this attribute? */
+ oldtup = SearchSysCache1(STATEXTOID,
+
ObjectIdGetDatum(statOid));
+
+ if (!HeapTupleIsValid(oldtup))
+ elog(ERROR, "cache lookup failed for extended statistics %u",
statOid);
+
+ /* replace it */
+ stup = heap_modify_tuple(oldtup,
+ RelationGetDescr(sd),
+ values,
+ nulls,
+ replaces);
+ ReleaseSysCache(oldtup);
+ CatalogTupleUpdate(sd, &stup->t_self, stup);
+
+ heap_freetuple(stup);
+ heap_close(sd, RowExclusiveLock);
+}
+
+/* multi-variate stats comparator */
+
+/*
+ * qsort_arg comparator for sorting Datums (MV stats)
+ *
+ * This does not maintain the tupnoLink array.
+ */
+int
+compare_scalars_simple(const void *a, const void *b, void *arg)
+{
+ Datum da = *(Datum *) a;
+ Datum db = *(Datum *) b;
+ SortSupport ssup = (SortSupport) arg;
+
+ return ApplySortComparator(da, false, db, false, ssup);
+}
+
+/*
+ * qsort_arg comparator for sorting data when partitioning a MV bucket
+ */
+int
+compare_scalars_partition(const void *a, const void *b, void *arg)
+{
+ Datum da = ((ScalarItem *) a)->value;
+ Datum db = ((ScalarItem *) b)->value;
+ SortSupport ssup = (SortSupport) arg;
+
+ return ApplySortComparator(da, false, db, false, ssup);
+}
+
+/* initialize multi-dimensional sort */
+MultiSortSupport
+multi_sort_init(int ndims)
+{
+ MultiSortSupport mss;
+
+ Assert(ndims >= 2);
+
+ mss = (MultiSortSupport) palloc0(offsetof(MultiSortSupportData, ssup)
+
+sizeof(SortSupportData) * ndims);
+
+ mss->ndims = ndims;
+
+ return mss;
+}
+
+/*
+ * Prepare sort support info for dimension 'dim' (index into vacattrstats) to
+ * 'mss', at the position 'sortdim'
+ */
+void
+multi_sort_add_dimension(MultiSortSupport mss, int sortdim,
+ int dim, VacAttrStats
**vacattrstats)
+{
+ /* first, lookup StdAnalyzeData for the dimension (attribute) */
+ SortSupportData ssup;
+ StdAnalyzeData *tmp = (StdAnalyzeData *) vacattrstats[dim]->extra_data;
+
+ Assert(mss != NULL);
+ Assert(sortdim < mss->ndims);
+
+ /* initialize sort support, etc. */
+ memset(&ssup, 0, sizeof(ssup));
+ ssup.ssup_cxt = CurrentMemoryContext;
+
+ /* We always use the default collation for statistics */
+ ssup.ssup_collation = DEFAULT_COLLATION_OID;
+ ssup.ssup_nulls_first = false;
+
+ PrepareSortSupportFromOrderingOp(tmp->ltopr, &ssup);
+
+ mss->ssup[sortdim] = ssup;
+}
+
+/* compare all the dimensions in the selected order */
+int
+multi_sort_compare(const void *a, const void *b, void *arg)
+{
+ int i;
+ SortItem *ia = (SortItem *) a;
+ SortItem *ib = (SortItem *) b;
+
+ MultiSortSupport mss = (MultiSortSupport) arg;
+
+ for (i = 0; i < mss->ndims; i++)
+ {
+ int compare;
+
+ compare = ApplySortComparator(ia->values[i], ia->isnull[i],
+
ib->values[i], ib->isnull[i],
+
&mss->ssup[i]);
+
+ if (compare != 0)
+ return compare;
+ }
+
+ /* equal by default */
+ return 0;
+}
+
+/* compare selected dimension */
+int
+multi_sort_compare_dim(int dim, const SortItem *a, const SortItem *b,
+ MultiSortSupport mss)
+{
+ return ApplySortComparator(a->values[dim], a->isnull[dim],
+ b->values[dim],
b->isnull[dim],
+ &mss->ssup[dim]);
+}
+
+int
+multi_sort_compare_dims(int start, int end,
+ const SortItem *a, const
SortItem *b,
+ MultiSortSupport mss)
+{
+ int dim;
+
+ for (dim = start; dim <= end; dim++)
+ {
+ int r = ApplySortComparator(a->values[dim],
a->isnull[dim],
+
b->values[dim], b->isnull[dim],
+
&mss->ssup[dim]);
+
+ if (r != 0)
+ return r;
+ }
+
+ return 0;
+}
+
+bool
+stats_are_enabled(HeapTuple htup, char type)
+{
+ Datum datum;
+ bool isnull;
+ int i,
+ nenabled;
+ char *enabled;
+ ArrayType *enabledArray;
+
+ /* see which statistics are enabled */
+ datum = SysCacheGetAttr(STATEXTOID, htup,
+
Anum_pg_statistic_ext_staenabled, &isnull);
+
+ /* if there are no values in staenabled field, everything is enabled */
+ if (isnull || (datum == PointerGetDatum(NULL)))
+ return false;
+
+ /*
+ * We expect the array to be a 1-D CHAR array; verify that. We don't
need
+ * to use deconstruct_array() since the array data is just going to look
+ * like a C array of char values.
+ */
+ enabledArray = DatumGetArrayTypeP(datum);
+
+ if (ARR_NDIM(enabledArray) != 1 ||
+ ARR_HASNULL(enabledArray) ||
+ ARR_ELEMTYPE(enabledArray) != CHAROID)
+ elog(ERROR, "enabled statistics (staenabled) is not a 1-D char
array");
+
+ nenabled = ARR_DIMS(enabledArray)[0];
+ enabled = (char *) ARR_DATA_PTR(enabledArray);
+
+ for (i = 0; i < nenabled; i++)
+ if (enabled[i] == type)
+ return true;
+
+ return false;
+}
+
+bool
+stats_are_built(HeapTuple htup, char type)
+{
+ bool isnull;
+
+ switch (type)
+ {
+ case STATS_EXT_NDISTINCT:
+ SysCacheGetAttr(STATEXTOID, htup,
+
Anum_pg_statistic_ext_standistinct, &isnull);
+ break;
+
+ default:
+ elog(ERROR, "unexpected statistics type requested: %d",
type);
+ }
+
+ return !isnull;
+}
diff --git a/src/backend/statistics/mvdist.c b/src/backend/statistics/mvdist.c
new file mode 100644
index 0000000..8f318da
--- /dev/null
+++ b/src/backend/statistics/mvdist.c
@@ -0,0 +1,621 @@
+/*-------------------------------------------------------------------------
+ *
+ * mvdist.c
+ * POSTGRES multivariate ndistinct coefficients
+ *
+ * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ * src/backend/statistics/mvdist.c
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include <math.h>
+
+#include "access/htup_details.h"
+#include "catalog/pg_statistic_ext.h"
+#include "utils/fmgrprotos.h"
+#include "utils/lsyscache.h"
+#include "lib/stringinfo.h"
+#include "utils/syscache.h"
+#include "statistics/common.h"
+#include "statistics/stats.h"
+
+
+static double estimate_ndistinct(double totalrows, int numrows, int d, int f1);
+
+/* internal state for generator of k-combinations of n elements */
+typedef struct CombinationGeneratorData
+{
+
+ int k; /* size of the
combination */
+ int current; /* index of the next
combination to return */
+
+ int ncombinations; /* number of combinations (size
of array) */
+ AttrNumber *combinations; /* array of pre-built combinations */
+
+} CombinationGeneratorData;
+
+typedef CombinationGeneratorData *CombinationGenerator;
+
+/* generator API */
+static CombinationGenerator generator_init(int2vector *attrs, int k);
+static void generator_free(CombinationGenerator state);
+static AttrNumber *generator_next(CombinationGenerator state, int2vector
*attrs);
+
+static int n_choose_k(int n, int k);
+static int num_combinations(int n);
+static double ndistinct_for_combination(double totalrows, int numrows,
+ HeapTuple *rows, int2vector *attrs,
VacAttrStats **stats,
+ int k, AttrNumber
*combination);
+
+/*
+ * Compute ndistinct coefficient for the combination of attributes. This
+ * computes the ndistinct estimate using the same estimator used in analyze.c
+ * and then computes the coefficient.
+ */
+MVNDistinct
+build_ext_ndistinct(double totalrows, int numrows, HeapTuple *rows,
+ int2vector *attrs, VacAttrStats **stats)
+{
+ int i,
+ k;
+ int numattrs = attrs->dim1;
+ int numcombs = num_combinations(numattrs);
+
+ MVNDistinct result;
+
+ result = palloc0(offsetof(MVNDistinctData, items) +
+ numcombs * sizeof(MVNDistinctItem));
+
+ result->nitems = numcombs;
+
+ i = 0;
+ for (k = 2; k <= numattrs; k++)
+ {
+ AttrNumber *combination;
+ CombinationGenerator generator;
+
+ generator = generator_init(attrs, k);
+
+ while ((combination = generator_next(generator, attrs)))
+ {
+ MVNDistinctItem *item = &result->items[i++];
+
+ item->nattrs = k;
+ item->ndistinct = ndistinct_for_combination(totalrows,
numrows, rows,
+
attrs, stats, k, combination);
+
+ item->attrs = palloc(k * sizeof(AttrNumber));
+ memcpy(item->attrs, combination, k *
sizeof(AttrNumber));
+
+ /* must not overflow the output array */
+ Assert(i <= result->nitems);
+ }
+
+ generator_free(generator);
+ }
+
+ /* must consume exactly the whole output array */
+ Assert(i == result->nitems);
+
+ return result;
+}
+
+/*
+ * ndistinct_for_combination
+ * Estimates number of distinct values in a combination of columns.
+ *
+ * This uses the same ndistinct estimator as compute_scalar_stats() in
+ * ANALYZE, i.e.,
+ * n*d / (n - f1 + f1*n/N)
+ *
+ * except that instead of values in a single column we are dealing with
+ * combination of multiple columns.
+ */
+static double
+ndistinct_for_combination(double totalrows, int numrows, HeapTuple *rows,
+ int2vector *attrs,
VacAttrStats **stats,
+ int k, AttrNumber
*combination)
+{
+ int i,
+ j;
+ int f1,
+ cnt,
+ d;
+ int nmultiple,
+ summultiple;
+ bool *isnull;
+ Datum *values;
+ SortItem *items;
+ MultiSortSupport mss;
+
+ /*
+ * It's possible to sort the sample rows directly, but this seemed
somehow
+ * simpler / less error prone. Another option would be to allocate the
+ * arrays for each SortItem separately, but that'd be significant
overhead
+ * (not just CPU, but especially memory bloat).
+ */
+ mss = multi_sort_init(k);
+ items = (SortItem *) palloc0(numrows * sizeof(SortItem));
+ values = (Datum *) palloc0(sizeof(Datum) * numrows * k);
+ isnull = (bool *) palloc0(sizeof(bool) * numrows * k);
+
+ Assert((k >= 2) && (k <= attrs->dim1));
+
+ for (i = 0; i < numrows; i++)
+ {
+ items[i].values = &values[i * k];
+ items[i].isnull = &isnull[i * k];
+ }
+
+ for (i = 0; i < k; i++)
+ {
+ /* prepare the sort function for the first dimension */
+ multi_sort_add_dimension(mss, i, combination[i], stats);
+
+ /* accumulate all the data into the array and sort it */
+ for (j = 0; j < numrows; j++)
+ {
+ items[j].values[i] =
+ heap_getattr(rows[j],
attrs->values[combination[i]],
+
stats[combination[i]]->tupDesc,
+ &items[j].isnull[i]);
+ }
+ }
+
+ qsort_arg((void *) items, numrows, sizeof(SortItem),
+ multi_sort_compare, mss);
+
+ /* count number of distinct combinations */
+
+ f1 = 0;
+ cnt = 1;
+ d = 1;
+ for (i = 1; i < numrows; i++)
+ {
+ if (multi_sort_compare(&items[i], &items[i - 1], mss) != 0)
+ {
+ if (cnt == 1)
+ f1 += 1;
+ else
+ {
+ nmultiple += 1;
+ summultiple += cnt;
+ }
+
+ d++;
+ cnt = 0;
+ }
+
+ cnt += 1;
+ }
+
+ if (cnt == 1)
+ f1 += 1;
+ else
+ {
+ nmultiple += 1;
+ summultiple += cnt;
+ }
+
+ return estimate_ndistinct(totalrows, numrows, d, f1);
+}
+
+MVNDistinct
+load_ext_ndistinct(Oid mvoid)
+{
+ bool isnull = false;
+ Datum ndist;
+
+ /*
+ * Prepare to scan pg_statistic_ext for entries having indrelid = this
+ * rel.
+ */
+ HeapTuple htup = SearchSysCache1(STATEXTOID,
ObjectIdGetDatum(mvoid));
+
+ Assert(stats_are_enabled(htup, STATS_EXT_NDISTINCT));
+ Assert(stats_are_built(htup, STATS_EXT_NDISTINCT));
+
+ ndist = SysCacheGetAttr(STATEXTOID, htup,
+
Anum_pg_statistic_ext_standistinct, &isnull);
+
+ Assert(!isnull);
+
+ ReleaseSysCache(htup);
+
+ return deserialize_ext_ndistinct(DatumGetByteaP(ndist));
+}
+
+/* The Duj1 estimator (already used in analyze.c). */
+static double
+estimate_ndistinct(double totalrows, int numrows, int d, int f1)
+{
+ double numer,
+ denom,
+ ndistinct;
+
+ numer = (double) numrows *(double) d;
+
+ denom = (double) (numrows - f1) +
+ (double) f1 *(double) numrows / totalrows;
+
+ ndistinct = numer / denom;
+
+ /* Clamp to sane range in case of roundoff error */
+ if (ndistinct < (double) d)
+ ndistinct = (double) d;
+
+ if (ndistinct > totalrows)
+ ndistinct = totalrows;
+
+ return floor(ndistinct + 0.5);
+}
+
+/*
+ * pg_ndistinct_in - input routine for type pg_ndistinct.
+ *
+ * pg_ndistinct is real enough to be a table column, but it has no operations
+ * of its own, and disallows input too
+ *
+ * XXX This is inspired by what pg_node_tree does.
+ */
+Datum
+pg_ndistinct_in(PG_FUNCTION_ARGS)
+{
+ /*
+ * pg_node_list stores the data in binary form and parsing text input is
+ * not needed, so disallow this.
+ */
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cannot accept a value of type %s",
"pg_ndistinct")));
+
+ PG_RETURN_VOID(); /* keep compiler quiet */
+}
+
+/*
+ * pg_ndistinct - output routine for type pg_ndistinct.
+ *
+ * histograms are serialized into a bytea value, so we simply call byteaout()
+ * to serialize the value into text. But it'd be nice to serialize that into
+ * a meaningful representation (e.g. for inspection by people).
+ */
+Datum
+pg_ndistinct_out(PG_FUNCTION_ARGS)
+{
+ int i,
+ j;
+ StringInfoData str;
+
+ bytea *data = PG_GETARG_BYTEA_PP(0);
+
+ MVNDistinct ndist = deserialize_ext_ndistinct(data);
+
+ initStringInfo(&str);
+ appendStringInfoChar(&str, '[');
+
+ for (i = 0; i < ndist->nitems; i++)
+ {
+ MVNDistinctItem item = ndist->items[i];
+
+ if (i > 0)
+ appendStringInfoString(&str, ", ");
+
+ appendStringInfoChar(&str, '{');
+
+ for (j = 0; j < item.nattrs; j++)
+ {
+ if (j > 0)
+ appendStringInfoString(&str, ", ");
+
+ appendStringInfo(&str, "%d", item.attrs[j]);
+ }
+
+ appendStringInfo(&str, ", %f", item.ndistinct);
+
+ appendStringInfoChar(&str, '}');
+ }
+
+ appendStringInfoChar(&str, ']');
+
+ PG_RETURN_CSTRING(str.data);
+}
+
+/*
+ * pg_ndistinct_recv - binary input routine for type pg_ndistinct.
+ */
+Datum
+pg_ndistinct_recv(PG_FUNCTION_ARGS)
+{
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cannot accept a value of type %s",
"pg_ndistinct")));
+
+ PG_RETURN_VOID(); /* keep compiler quiet */
+}
+
+/*
+ * pg_ndistinct_send - binary output routine for type pg_ndistinct.
+ *
+ * XXX Histograms are serialized into a bytea value, so let's just send that.
+ */
+Datum
+pg_ndistinct_send(PG_FUNCTION_ARGS)
+{
+ return byteasend(fcinfo);
+}
+
+/*
+ * n_choose_k
+ * computes binomial coefficients using an algorithm that is both
+ * efficient and prevents overflows
+ */
+static int
+n_choose_k(int n, int k)
+{
+ int d,
+ r;
+
+ Assert((k > 0) && (n >= k));
+
+ /* use symmetry of the binomial coefficients */
+ k = Min(k, n - k);
+
+ r = 1;
+ for (d = 1; d <= k; ++d)
+ {
+ r *= n--;
+ r /= d;
+ }
+
+ return r;
+}
+
+/*
+ * num_combinations
+ * computes number of combinations, excluding single-value
combinations
+ */
+static int
+num_combinations(int n)
+{
+ int k;
+ int ncombs = 1;
+
+ for (k = 1; k <= n; k++)
+ ncombs *= 2;
+
+ ncombs -= (n + 1);
+
+ return ncombs;
+}
+
+/*
+ * generate all combinations (k elements from n)
+ */
+static void
+generate_combinations_recurse(CombinationGenerator state, AttrNumber n,
+ int index, AttrNumber
start, AttrNumber *current)
+{
+ /* If we haven't filled all the elements, simply recurse. */
+ if (index < state->k)
+ {
+ AttrNumber i;
+
+ /*
+ * The values have to be in ascending order, so make sure we
start
+ * with the value passed by parameter.
+ */
+
+ for (i = start; i < n; i++)
+ {
+ current[index] = i;
+ generate_combinations_recurse(state, n, (index + 1), (i
+ 1), current);
+ }
+
+ return;
+ }
+ else
+ {
+ /* we got a correct combination */
+ state->combinations = (AttrNumber *)
repalloc(state->combinations,
+ state->k * (state->current + 1) *
sizeof(AttrNumber));
+ memcpy(&state->combinations[(state->k * state->current)],
+ current, state->k * sizeof(AttrNumber));
+ state->current++;
+ }
+}
+
+/* generate all k-combinations of n elements */
+static void
+generate_combinations(CombinationGenerator state, int n)
+{
+ AttrNumber *current = (AttrNumber *) palloc0(sizeof(AttrNumber) *
state->k);
+
+ generate_combinations_recurse(state, n, 0, 0, current);
+
+ pfree(current);
+}
+
+/*
+ * initialize the generator of combinations, and prebuild them.
+ *
+ * This pre-builds all the combinations. We could also generate them in
+ * generator_next(), but this seems simpler.
+ */
+static CombinationGenerator
+generator_init(int2vector *attrs, int k)
+{
+ int n = attrs->dim1;
+ CombinationGenerator state;
+
+ Assert((n >= k) && (k > 0));
+
+ /* allocate the generator state as a single chunk of memory */
+ state = (CombinationGenerator)
palloc0(sizeof(CombinationGeneratorData));
+ state->combinations = (AttrNumber *) palloc(k * sizeof(AttrNumber));
+
+ state->ncombinations = n_choose_k(n, k);
+ state->current = 0;
+ state->k = k;
+
+ /* now actually pre-generate all the combinations */
+ generate_combinations(state, n);
+
+ /* make sure we got the expected number of combinations */
+ Assert(state->current == state->ncombinations);
+
+ /* reset the number, so we start with the first one */
+ state->current = 0;
+
+ return state;
+}
+
+/* free the generator state */
+static void
+generator_free(CombinationGenerator state)
+{
+ /* we've allocated a single chunk, so just free it */
+ pfree(state);
+}
+
+/* generate next combination */
+static AttrNumber *
+generator_next(CombinationGenerator state, int2vector *attrs)
+{
+ if (state->current == state->ncombinations)
+ return NULL;
+
+ return &state->combinations[state->k * state->current++];
+}
+
+/*
+ * serialize list of ndistinct items into a bytea
+ */
+bytea *
+serialize_ext_ndistinct(MVNDistinct ndistinct)
+{
+ int i;
+ bytea *output;
+ char *tmp;
+
+ /* we need to store nitems */
+ Size len = VARHDRSZ + offsetof(MVNDistinctData, items) +
+ ndistinct->nitems * offsetof(MVNDistinctItem, attrs);
+
+ /* and also include space for the actual attribute numbers */
+ for (i = 0; i < ndistinct->nitems; i++)
+ len += (sizeof(AttrNumber) * ndistinct->items[i].nattrs);
+
+ output = (bytea *) palloc0(len);
+ SET_VARSIZE(output, len);
+
+ tmp = VARDATA(output);
+
+ ndistinct->magic = STATS_NDISTINCT_MAGIC;
+ ndistinct->type = STATS_NDISTINCT_TYPE_BASIC;
+
+ /* first, store the number of items */
+ memcpy(tmp, ndistinct, offsetof(MVNDistinctData, items));
+ tmp += offsetof(MVNDistinctData, items);
+
+ /*
+ * store number of attributes and attribute numbers for each ndistinct
+ * entry
+ */
+ for (i = 0; i < ndistinct->nitems; i++)
+ {
+ MVNDistinctItem item = ndistinct->items[i];
+
+ memcpy(tmp, &item, offsetof(MVNDistinctItem, attrs));
+ tmp += offsetof(MVNDistinctItem, attrs);
+
+ memcpy(tmp, item.attrs, sizeof(AttrNumber) * item.nattrs);
+ tmp += sizeof(AttrNumber) * item.nattrs;
+
+ Assert(tmp <= ((char *) output + len));
+ }
+
+ return output;
+}
+
+/*
+ * Reads serialized ndistinct into MVNDistinct structure.
+ */
+MVNDistinct
+deserialize_ext_ndistinct(bytea *data)
+{
+ int i;
+ Size expected_size;
+ MVNDistinct ndistinct;
+ char *tmp;
+
+ if (data == NULL)
+ return NULL;
+
+ if (VARSIZE_ANY_EXHDR(data) < offsetof(MVNDistinctData, items))
+ elog(ERROR, "invalid MVNDistinct size %ld (expected at least
%ld)",
+ VARSIZE_ANY_EXHDR(data), offsetof(MVNDistinctData,
items));
+
+ /* read the MVNDistinct header */
+ ndistinct = (MVNDistinct) palloc0(sizeof(MVNDistinctData));
+
+ /* initialize pointer to the data part (skip the varlena header) */
+ tmp = VARDATA_ANY(data);
+
+ /* get the header and perform basic sanity checks */
+ memcpy(ndistinct, tmp, offsetof(MVNDistinctData, items));
+ tmp += offsetof(MVNDistinctData, items);
+
+ if (ndistinct->magic != STATS_NDISTINCT_MAGIC)
+ elog(ERROR, "invalid ndistinct magic %d (expected %d)",
+ ndistinct->magic, STATS_NDISTINCT_MAGIC);
+
+ if (ndistinct->type != STATS_NDISTINCT_TYPE_BASIC)
+ elog(ERROR, "invalid ndistinct type %d (expected %d)",
+ ndistinct->type, STATS_NDISTINCT_TYPE_BASIC);
+
+ Assert(ndistinct->nitems > 0);
+
+ /* what minimum bytea size do we expect for those parameters */
+ expected_size = offsetof(MVNDistinctData, items) +
+ ndistinct->nitems * (offsetof(MVNDistinctItem, attrs) +
+ sizeof(AttrNumber) *
2);
+
+ if (VARSIZE_ANY_EXHDR(data) < expected_size)
+ elog(ERROR, "invalid dependencies size %ld (expected at least
%ld)",
+ VARSIZE_ANY_EXHDR(data), expected_size);
+
+ /* allocate space for the ndistinct items */
+ ndistinct = repalloc(ndistinct, offsetof(MVNDistinctData, items) +
+ (ndistinct->nitems *
sizeof(MVNDistinctItem)));
+
+ for (i = 0; i < ndistinct->nitems; i++)
+ {
+ MVNDistinctItem *item = &ndistinct->items[i];
+
+ /* number of attributes */
+ memcpy(item, tmp, offsetof(MVNDistinctItem, attrs));
+ tmp += offsetof(MVNDistinctItem, attrs);
+
+ /* is the number of attributes valid? */
+ Assert((item->nattrs >= 2) && (item->nattrs <=
STATS_MAX_DIMENSIONS));
+
+ /* now that we know the number of attributes, allocate the
attribute */
+ item->attrs = (AttrNumber *) palloc0(item->nattrs *
sizeof(AttrNumber));
+
+ /* copy attribute numbers */
+ memcpy(item->attrs, tmp, sizeof(AttrNumber) * item->nattrs);
+ tmp += sizeof(AttrNumber) * item->nattrs;
+
+ /* still within the bytea */
+ Assert(tmp <= ((char *) data + VARSIZE_ANY(data)));
+ }
+
+ /* we should have consumed the whole bytea exactly */
+ Assert(tmp == ((char *) data + VARSIZE_ANY(data)));
+
+ return ndistinct;
+}
diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c
index 20b5273..0af8c34 100644
--- a/src/backend/tcop/utility.c
+++ b/src/backend/tcop/utility.c
@@ -1623,6 +1623,10 @@ ProcessUtilitySlow(ParseState *pstate,
commandCollected = true;
break;
+ case T_CreateStatsStmt: /* CREATE STATISTICS */
+ address = CreateStatistics((CreateStatsStmt *)
parsetree);
+ break;
+
default:
elog(ERROR, "unrecognized node type: %d",
(int) nodeTag(parsetree));
@@ -1988,6 +1992,8 @@ AlterObjectTypeCommandTag(ObjectType objtype)
break;
case OBJECT_SUBSCRIPTION:
tag = "ALTER SUBSCRIPTION";
+ case OBJECT_STATISTICS:
+ tag = "ALTER STATISTICS";
break;
default:
tag = "???";
@@ -2282,6 +2288,8 @@ CreateCommandTag(Node *parsetree)
break;
case OBJECT_PUBLICATION:
tag = "DROP PUBLICATION";
+ case OBJECT_STATISTICS:
+ tag = "DROP STATISTICS";
break;
default:
tag = "???";
@@ -2681,6 +2689,10 @@ CreateCommandTag(Node *parsetree)
tag = "EXECUTE";
break;
+ case T_CreateStatsStmt:
+ tag = "CREATE STATISTICS";
+ break;
+
case T_DeallocateStmt:
{
DeallocateStmt *stmt = (DeallocateStmt *)
parsetree;
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index 04bd9b9..5ea9e5b 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -126,6 +126,7 @@
#include "parser/parse_clause.h"
#include "parser/parse_coerce.h"
#include "parser/parsetree.h"
+#include "statistics/stats.h"
#include "utils/builtins.h"
#include "utils/bytea.h"
#include "utils/date.h"
@@ -208,6 +209,8 @@ static Const *string_to_const(const char *str, Oid
datatype);
static Const *string_to_bytea_const(const char *str, size_t str_len);
static List *add_predicate_to_quals(IndexOptInfo *index, List *indexQuals);
+static double find_ndistinct(PlannerInfo *root, RelOptInfo *rel, List
*varinfos,
+ bool *found);
/*
* eqsel - Selectivity of "=" for any data types.
@@ -3437,12 +3440,26 @@ estimate_num_groups(PlannerInfo *root, List
*groupExprs, double input_rows,
* don't know by how much. We should never clamp to
less than the
* largest ndistinct value for any of the Vars, though,
since
* there will surely be at least that many groups.
+ *
+ * However we don't need to do this if we have
ndistinct stats on
+ * the columns - in that case we can simply use the
coefficient to
+ * get the (probably way more accurate) estimate.
+ *
+ * XXX Might benefit from some refactoring, mixing the
ndistinct
+ * coefficients and clamp seems a bit unfortunate.
*/
double clamp = rel->tuples;
if (relvarcount > 1)
{
- clamp *= 0.1;
+ bool found;
+ double ndist = find_ndistinct(root,
rel, varinfos, &found);
+
+ if (found)
+ reldistinct = ndist;
+ else
+ clamp *= 0.1;
+
if (clamp < relmaxndistinct)
{
clamp = relmaxndistinct;
@@ -3451,6 +3468,7 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs,
double input_rows,
clamp = rel->tuples;
}
}
+
if (reldistinct > clamp)
reldistinct = clamp;
@@ -7592,3 +7610,155 @@ brincostestimate(PlannerInfo *root, IndexPath *path,
double loop_count,
/* XXX what about pages_per_range? */
}
+
+/*
+ * Find applicable ndistinct statistics and compute the coefficient to
+ * correct the estimate (simply a product of per-column ndistincts).
+ *
+ * XXX Currently we only look for a perfect match, i.e. a single ndistinct
+ * estimate exactly matching all the columns of the statistics. This may be
+ * a bit problematic as adding a column (not covered by the ndistinct stats)
+ * will prevent us from using the stats entirely. So instead this needs to
+ * estimate the covered attributes, and then combine that with the extra
+ * attributes somehow (probably the old way).
+ */
+static double
+find_ndistinct(PlannerInfo *root, RelOptInfo *rel, List *varinfos, bool *found)
+{
+ ListCell *lc;
+ Bitmapset *attnums = NULL;
+ VariableStatData vardata;
+
+ /* assume we haven't found any suitable ndistinct statistics */
+ *found = false;
+
+ /* bail out immediately if the table has no extended statistics */
+ if (!rel->statlist)
+ return 0.0;
+
+ foreach(lc, varinfos)
+ {
+ GroupVarInfo *varinfo = (GroupVarInfo *) lfirst(lc);
+
+ if (varinfo->rel != rel)
+ continue;
+
+ /* FIXME handle expressions in general only */
+
+ /*
+ * examine the variable (or expression) so that we know which
+ * attribute we're dealing with - we need this for matching the
+ * ndistinct coefficient
+ *
+ * FIXME probably might remember this from estimate_num_groups
+ */
+ examine_variable(root, varinfo->var, 0, &vardata);
+
+ if (HeapTupleIsValid(vardata.statsTuple))
+ {
+ Form_pg_statistic stats
+ = (Form_pg_statistic) GETSTRUCT(vardata.statsTuple);
+
+ attnums = bms_add_member(attnums, stats->staattnum);
+
+ ReleaseVariableStats(vardata);
+ }
+ }
+
+ /* look for a matching ndistinct statistics */
+ foreach(lc, rel->statlist)
+ {
+ int i,
+ k;
+ bool matches;
+ StatisticExtInfo *info = (StatisticExtInfo *) lfirst(lc);
+
+ /* skip statistics without ndistinct coefficient built */
+ if (!info->ndist_built)
+ continue;
+
+ /*
+ * Only ndistinct stats covering all Vars are acceptable, which
can't
+ * happen if the statistics has fewer attributes than we have
Vars.
+ */
+ if (bms_num_members(attnums) > info->stakeys->dim1)
+ continue;
+
+ /* check that all Vars are covered by the statistic */
+ matches = true; /* assume match until we find
unmatched
+ * attribute */
+ k = -1;
+ while ((k = bms_next_member(attnums, k)) >= 0)
+ {
+ bool attr_found = false;
+
+ for (i = 0; i < info->stakeys->dim1; i++)
+ {
+ if (info->stakeys->values[i] == k)
+ {
+ attr_found = true;
+ break;
+ }
+ }
+
+ /* found attribute not covered by this ndistinct stats,
skip */
+ if (!attr_found)
+ {
+ matches = false;
+ break;
+ }
+ }
+
+ if (!matches)
+ continue;
+
+ /* hey, this statistics matches! great, let's extract the value
*/
+ *found = true;
+
+ {
+ int j;
+ MVNDistinct stat = load_ext_ndistinct(info->statOid);
+
+ for (j = 0; j < stat->nitems; j++)
+ {
+ bool item_matches = true;
+ MVNDistinctItem *item = &stat->items[j];
+
+ /* not the right item (different number of
attributes) */
+ if (item->nattrs != bms_num_members(attnums))
+ continue;
+
+ /* check the attribute numbers */
+ k = -1;
+ while ((k = bms_next_member(attnums, k)) >= 0)
+ {
+ bool attr_found = false;
+
+ for (i = 0; i < item->nattrs; i++)
+ {
+ if
(info->stakeys->values[item->attrs[i]] == k)
+ {
+ attr_found = true;
+ break;
+ }
+ }
+
+ if (!attr_found)
+ {
+ item_matches = false;
+ break;
+ }
+ }
+
+ if (!item_matches)
+ continue;
+
+ return item->ndistinct;
+ }
+ }
+ }
+
+ Assert(!(*found));
+
+ return 0.0;
+}
diff --git a/src/backend/utils/cache/relcache.c
b/src/backend/utils/cache/relcache.c
index ce55fc5..a6b60c6 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -56,6 +56,7 @@
#include "catalog/pg_publication.h"
#include "catalog/pg_rewrite.h"
#include "catalog/pg_shseclabel.h"
+#include "catalog/pg_statistic_ext.h"
#include "catalog/pg_subscription.h"
#include "catalog/pg_tablespace.h"
#include "catalog/pg_trigger.h"
@@ -4452,6 +4453,82 @@ RelationGetIndexList(Relation relation)
}
/*
+ * RelationGetStatExtList
+ * get a list of OIDs of extended statistics on this relation
+ *
+ * The statistics list is created only if someone requests it, in a way
+ * similar to RelationGetIndexList(). We scan pg_statistic_ext to find
+ * relevant statistics, and add the list to the relcache entry so that we
+ * won't have to compute it again. Note that shared cache inval of a
+ * relcache entry will delete the old list and set rd_statvalid to 0,
+ * so that we must recompute the statistics list on next request. This
+ * handles creation or deletion of a statistic.
+ *
+ * The returned list is guaranteed to be sorted in order by OID, although
+ * this is not currently needed.
+ *
+ * Since shared cache inval causes the relcache's copy of the list to go away,
+ * we return a copy of the list palloc'd in the caller's context. The caller
+ * may list_free() the returned list after scanning it. This is necessary
+ * since the caller will typically be doing syscache lookups on the relevant
+ * statistics, and syscache lookup could cause SI messages to be processed!
+ */
+List *
+RelationGetStatExtList(Relation relation)
+{
+ Relation indrel;
+ SysScanDesc indscan;
+ ScanKeyData skey;
+ HeapTuple htup;
+ List *result;
+ List *oldlist;
+ MemoryContext oldcxt;
+
+ /* Quick exit if we already computed the list. */
+ if (relation->rd_statvalid != 0)
+ return list_copy(relation->rd_statlist);
+
+ /*
+ * We build the list we intend to return (in the caller's context) while
+ * doing the scan. After successfully completing the scan, we copy that
+ * list into the relcache entry. This avoids cache-context memory
leakage
+ * if we get some sort of error partway through.
+ */
+ result = NIL;
+
+ /* Prepare to scan pg_statistic_ext for entries having starelid = this
rel. */
+ ScanKeyInit(&skey,
+ Anum_pg_statistic_ext_starelid,
+ BTEqualStrategyNumber, F_OIDEQ,
+ ObjectIdGetDatum(RelationGetRelid(relation)));
+
+ indrel = heap_open(StatisticExtRelationId, AccessShareLock);
+ indscan = systable_beginscan(indrel, StatisticExtRelidIndexId, true,
+ NULL, 1,
&skey);
+
+ while (HeapTupleIsValid(htup = systable_getnext(indscan)))
+ /* TODO maybe include only already built statistics? */
+ result = insert_ordered_oid(result, HeapTupleGetOid(htup));
+
+ systable_endscan(indscan);
+
+ heap_close(indrel, AccessShareLock);
+
+ /* Now save a copy of the completed list in the relcache entry. */
+ oldcxt = MemoryContextSwitchTo(CacheMemoryContext);
+ oldlist = relation->rd_statlist;
+ relation->rd_statlist = list_copy(result);
+
+ relation->rd_statvalid = true;
+ MemoryContextSwitchTo(oldcxt);
+
+ /* Don't leak the old list, if there is one */
+ list_free(oldlist);
+
+ return result;
+}
+
+/*
* insert_ordered_oid
* Insert a new Oid into a sorted list of Oids, preserving ordering
*
@@ -5560,6 +5637,8 @@ load_relcache_init_file(bool shared)
rel->rd_pkattr = NULL;
rel->rd_idattr = NULL;
rel->rd_pubactions = NULL;
+ rel->rd_statvalid = false;
+ rel->rd_statlist = NIL;
rel->rd_createSubid = InvalidSubTransactionId;
rel->rd_newRelfilenodeSubid = InvalidSubTransactionId;
rel->rd_amcache = NULL;
diff --git a/src/backend/utils/cache/syscache.c
b/src/backend/utils/cache/syscache.c
index b1c0b4b..4a9cb76 100644
--- a/src/backend/utils/cache/syscache.c
+++ b/src/backend/utils/cache/syscache.c
@@ -61,6 +61,7 @@
#include "catalog/pg_shseclabel.h"
#include "catalog/pg_replication_origin.h"
#include "catalog/pg_statistic.h"
+#include "catalog/pg_statistic_ext.h"
#include "catalog/pg_subscription.h"
#include "catalog/pg_tablespace.h"
#include "catalog/pg_transform.h"
@@ -725,6 +726,28 @@ static const struct cachedesc cacheinfo[] = {
},
32
},
+ {StatisticExtRelationId, /* STATEXTNAMENSP */
+ StatisticExtNameIndexId,
+ 2,
+ {
+ Anum_pg_statistic_ext_staname,
+ Anum_pg_statistic_ext_stanamespace,
+ 0,
+ 0
+ },
+ 4
+ },
+ {StatisticExtRelationId, /* STATEXTOID */
+ StatisticExtOidIndexId,
+ 1,
+ {
+ ObjectIdAttributeNumber,
+ 0,
+ 0,
+ 0
+ },
+ 4
+ },
{StatisticRelationId, /* STATRELATTINH */
StatisticRelidAttnumInhIndexId,
3,
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 61a3e2a..3001dee 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2320,6 +2320,50 @@ describeOneTableDetails(const char *schemaname,
PQclear(result);
}
+ /* print any extended statistics */
+ if (pset.sversion >= 100000)
+ {
+ printfPQExpBuffer(&buf,
+ "SELECT oid,
stanamespace::regnamespace AS nsp, staname, stakeys,\n"
+ "
(staenabled::char[] @> '{d}'::char[]) AS ndist_enabled,\n"
+ " (standistinct IS
NOT NULL) AS ndist_built,\n"
+ " (SELECT
string_agg(attname::text,', ')\n"
+ " FROM ((SELECT
unnest(stakeys) AS attnum) s\n"
+ " JOIN
pg_attribute a ON (starelid = a.attrelid and a.attnum = s.attnum))) AS
attnums\n"
+ "FROM pg_statistic_ext stat WHERE starelid = '%s'
ORDER BY 1;",
+ oid);
+
+ result = PSQLexec(buf.data);
+ if (!result)
+ goto error_return;
+ else
+ tuples = PQntuples(result);
+
+ if (tuples > 0)
+ {
+ printTableAddFooter(&cont, _("Statistics:"));
+ for (i = 0; i < tuples; i++)
+ {
+ printfPQExpBuffer(&buf, " ");
+
+ /* statistics name (qualified with
namespace) */
+ appendPQExpBuffer(&buf, "\"%s.%s\" ",
+
PQgetvalue(result, i, 1),
+
PQgetvalue(result, i, 2));
+
+ /* options */
+ if (!strcmp(PQgetvalue(result, i, 4),
"t"))
+ appendPQExpBuffer(&buf,
"(dependencies)");
+
+ appendPQExpBuffer(&buf, " ON (%s)",
+
PQgetvalue(result, i, 6));
+
+ printTableAddFooter(&cont, buf.data);
+ }
+ }
+ PQclear(result);
+ }
+
/* print rules */
if (tableinfo.hasrules && tableinfo.relkind != RELKIND_MATVIEW)
{
diff --git a/src/include/catalog/dependency.h b/src/include/catalog/dependency.h
index 10759c7..9effbce 100644
--- a/src/include/catalog/dependency.h
+++ b/src/include/catalog/dependency.h
@@ -147,6 +147,7 @@ typedef enum ObjectClass
OCLASS_REWRITE, /* pg_rewrite */
OCLASS_TRIGGER, /* pg_trigger */
OCLASS_SCHEMA, /* pg_namespace */
+ OCLASS_STATISTIC_EXT, /* pg_statistic_ext */
OCLASS_TSPARSER, /* pg_ts_parser */
OCLASS_TSDICT, /* pg_ts_dict */
OCLASS_TSTEMPLATE, /* pg_ts_template */
diff --git a/src/include/catalog/heap.h b/src/include/catalog/heap.h
index 1187797..473fe17 100644
--- a/src/include/catalog/heap.h
+++ b/src/include/catalog/heap.h
@@ -119,6 +119,7 @@ extern void RemoveAttrDefault(Oid relid, AttrNumber attnum,
DropBehavior behavior, bool complain, bool
internal);
extern void RemoveAttrDefaultById(Oid attrdefId);
extern void RemoveStatistics(Oid relid, AttrNumber attnum);
+extern void RemoveStatisticsExt(Oid relid, AttrNumber attnum);
extern Form_pg_attribute SystemAttributeDefinition(AttrNumber attno,
bool relhasoids);
diff --git a/src/include/catalog/indexing.h b/src/include/catalog/indexing.h
index 6bce732..8130581 100644
--- a/src/include/catalog/indexing.h
+++ b/src/include/catalog/indexing.h
@@ -182,6 +182,13 @@ DECLARE_UNIQUE_INDEX(pg_largeobject_loid_pn_index, 2683,
on pg_largeobject using
DECLARE_UNIQUE_INDEX(pg_largeobject_metadata_oid_index, 2996, on
pg_largeobject_metadata using btree(oid oid_ops));
#define LargeObjectMetadataOidIndexId 2996
+DECLARE_UNIQUE_INDEX(pg_statistic_ext_oid_index, 3380, on pg_statistic_ext
using btree(oid oid_ops));
+#define StatisticExtOidIndexId 3380
+DECLARE_UNIQUE_INDEX(pg_statistic_ext_name_index, 3997, on pg_statistic_ext
using btree(staname name_ops, stanamespace oid_ops));
+#define StatisticExtNameIndexId 3997
+DECLARE_INDEX(pg_statistic_ext_relid_index, 3379, on pg_statistic_ext using
btree(starelid oid_ops));
+#define StatisticExtRelidIndexId 3379
+
DECLARE_UNIQUE_INDEX(pg_namespace_nspname_index, 2684, on pg_namespace using
btree(nspname name_ops));
#define NamespaceNameIndexId 2684
DECLARE_UNIQUE_INDEX(pg_namespace_oid_index, 2685, on pg_namespace using
btree(oid oid_ops));
diff --git a/src/include/catalog/namespace.h b/src/include/catalog/namespace.h
index dbeb25b..35e0e2b 100644
--- a/src/include/catalog/namespace.h
+++ b/src/include/catalog/namespace.h
@@ -141,6 +141,8 @@ extern Oid get_collation_oid(List *collname, bool
missing_ok);
extern Oid get_conversion_oid(List *conname, bool missing_ok);
extern Oid FindDefaultConversionProc(int32 for_encoding, int32
to_encoding);
+extern Oid get_statistics_oid(List *names, bool missing_ok);
+
/* initialization & transaction cleanup code */
extern void InitializeSearchPath(void);
extern void AtEOXact_Namespace(bool isCommit, bool parallel);
diff --git a/src/include/catalog/pg_cast.h b/src/include/catalog/pg_cast.h
index 80a40ab..5bcdce7 100644
--- a/src/include/catalog/pg_cast.h
+++ b/src/include/catalog/pg_cast.h
@@ -254,6 +254,10 @@ DATA(insert ( 23 18 78 e f ));
/* pg_node_tree can be coerced to, but not from, text */
DATA(insert ( 194 25 0 i b ));
+/* pg_ndistinct can be coerced to, but not from, bytea and text */
+DATA(insert ( 3353 17 0 i b ));
+DATA(insert ( 3353 25 0 i i ));
+
/*
* Datetime category
*/
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index ec4aedb..05baa80 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -2726,6 +2726,15 @@ DESCR("current user privilege on any column by rel
name");
DATA(insert OID = 3029 ( has_any_column_privilege PGNSP PGUID 12 10 0
0 0 f f f f t f s s 2 0 16 "26 25" _null_ _null_ _null_ _null_ _null_
has_any_column_privilege_id _null_ _null_ _null_ ));
DESCR("current user privilege on any column by rel oid");
+DATA(insert OID = 3354 ( pg_ndistinct_in PGNSP PGUID 12 1 0 0 0 f f f f
t f i s 1 0 3353 "2275" _null_ _null_ _null_ _null_ _null_ pg_ndistinct_in
_null_ _null_ _null_ ));
+DESCR("I/O");
+DATA(insert OID = 3355 ( pg_ndistinct_out PGNSP PGUID 12 1 0 0 0 f f f f
t f i s 1 0 2275 "3353" _null_ _null_ _null_ _null_ _null_ pg_ndistinct_out
_null_ _null_ _null_ ));
+DESCR("I/O");
+DATA(insert OID = 3356 ( pg_ndistinct_recv PGNSP PGUID 12 1 0 0 0 f f f f t f
s s 1 0 3353 "2281" _null_ _null_ _null_ _null_ _null_ pg_ndistinct_recv _null_
_null_ _null_ ));
+DESCR("I/O");
+DATA(insert OID = 3357 ( pg_ndistinct_send PGNSP PGUID 12 1 0 0 0 f f f f t f
s s 1 0 17 "3353" _null_ _null_ _null_ _null_ _null_ pg_ndistinct_send _null_
_null_ _null_ ));
+DESCR("I/O");
+
DATA(insert OID = 1928 ( pg_stat_get_numscans PGNSP PGUID 12
1 0 0 0 f f f f t f s r 1 0 20 "26" _null_ _null_ _null_ _null_ _null_
pg_stat_get_numscans _null_ _null_ _null_ ));
DESCR("statistics: number of scans done for table/index");
DATA(insert OID = 1929 ( pg_stat_get_tuples_returned PGNSP PGUID 12 1 0 0 0
f f f f t f s r 1 0 20 "26" _null_ _null_ _null_ _null_ _null_
pg_stat_get_tuples_returned _null_ _null_ _null_ ));
diff --git a/src/include/catalog/pg_statistic_ext.h
b/src/include/catalog/pg_statistic_ext.h
new file mode 100644
index 0000000..94b23a2
--- /dev/null
+++ b/src/include/catalog/pg_statistic_ext.h
@@ -0,0 +1,74 @@
+/*-------------------------------------------------------------------------
+ *
+ * pg_statistic_ext.h
+ * definition of the system "extended statistic" relation
(pg_statistic_ext)
+ * along with the relation's initial contents.
+ *
+ *
+ * Portions Copyright (c) 1996-2014, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/catalog/pg_statistic_ext.h
+ *
+ * NOTES
+ * the genbki.pl script reads this file and generates .bki
+ * information from the DATA() statements.
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef PG_STATISTIC_EXT_H
+#define PG_STATISTIC_EXT_H
+
+#include "catalog/genbki.h"
+
+/* ----------------
+ * pg_statistic_ext definition. cpp turns this into
+ * typedef struct FormData_pg_statistic_ext
+ * ----------------
+ */
+#define StatisticExtRelationId 3381
+
+CATALOG(pg_statistic_ext,3381)
+{
+ /* These fields form the unique key for the entry: */
+ Oid starelid; /* relation containing
attributes */
+ NameData staname; /* statistics name */
+ Oid stanamespace; /* OID of namespace containing
this statistics */
+ Oid staowner; /* statistics owner */
+
+ /*
+ * variable-length fields start here, but we allow direct access to
+ * stakeys
+ */
+ int2vector stakeys; /* array of column keys */
+
+#ifdef CATALOG_VARLEN
+ char staenabled[1]; /* statistics requested to build */
+ pg_ndistinct standistinct; /* ndistinct coefficients (serialized)
*/
+#endif
+
+} FormData_pg_statistic_ext;
+
+/* ----------------
+ * Form_pg_statistic_ext corresponds to a pointer to a tuple with
+ * the format of pg_statistic_ext relation.
+ * ----------------
+ */
+typedef FormData_pg_statistic_ext *Form_pg_statistic_ext;
+
+/* ----------------
+ * compiler constants for pg_statistic_ext
+ * ----------------
+ */
+#define Natts_pg_statistic_ext 7
+#define Anum_pg_statistic_ext_starelid 1
+#define Anum_pg_statistic_ext_staname 2
+#define Anum_pg_statistic_ext_stanamespace 3
+#define Anum_pg_statistic_ext_staowner 4
+#define Anum_pg_statistic_ext_stakeys 5
+#define Anum_pg_statistic_ext_staenabled 6
+#define Anum_pg_statistic_ext_standistinct 7
+
+#define STATS_EXT_NDISTINCT 'd'
+
+#endif /* PG_STATISTIC_EXT_H */
diff --git a/src/include/catalog/pg_type.h b/src/include/catalog/pg_type.h
index 6e4c65e..9c9caf3 100644
--- a/src/include/catalog/pg_type.h
+++ b/src/include/catalog/pg_type.h
@@ -364,6 +364,10 @@ DATA(insert OID = 194 ( pg_node_tree PGNSP PGUID -1
f b S f t \054 0 0 0 pg_node
DESCR("string representing an internal node tree");
#define PGNODETREEOID 194
+DATA(insert OID = 3353 ( pg_ndistinct PGNSP PGUID -1 f b S f t \054 0
0 0 pg_ndistinct_in pg_ndistinct_out pg_ndistinct_recv pg_ndistinct_send - - -
i x f 0 -1 0 100 _null_ _null_ _null_ ));
+DESCR("multivariate ndistinct coefficients");
+#define PGNDISTINCTOID 3353
+
DATA(insert OID = 32 ( pg_ddl_command PGNSP PGUID SIZEOF_POINTER t p P f t
\054 0 0 0 pg_ddl_command_in pg_ddl_command_out pg_ddl_command_recv
pg_ddl_command_send - - - ALIGNOF_POINTER p f 0 -1 0 0 _null_ _null_ _null_ ));
DESCR("internal type for passing CollectedCommand");
#define PGDDLCOMMANDOID 32
diff --git a/src/include/catalog/toasting.h b/src/include/catalog/toasting.h
index db7f145..00d0a83 100644
--- a/src/include/catalog/toasting.h
+++ b/src/include/catalog/toasting.h
@@ -53,6 +53,7 @@ DECLARE_TOAST(pg_proc, 2836, 2837);
DECLARE_TOAST(pg_rewrite, 2838, 2839);
DECLARE_TOAST(pg_seclabel, 3598, 3599);
DECLARE_TOAST(pg_statistic, 2840, 2841);
+DECLARE_TOAST(pg_statistic_ext, 3439, 3440);
DECLARE_TOAST(pg_trigger, 2336, 2337);
/* shared catalogs */
diff --git a/src/include/commands/defrem.h b/src/include/commands/defrem.h
index 8740cee..c323e81 100644
--- a/src/include/commands/defrem.h
+++ b/src/include/commands/defrem.h
@@ -77,6 +77,10 @@ extern ObjectAddress DefineOperator(List *names, List
*parameters);
extern void RemoveOperatorById(Oid operOid);
extern ObjectAddress AlterOperator(AlterOperatorStmt *stmt);
+/* commands/statscmds.c */
+extern ObjectAddress CreateStatistics(CreateStatsStmt *stmt);
+extern void RemoveStatisticsById(Oid statsOid);
+
/* commands/aggregatecmds.c */
extern ObjectAddress DefineAggregate(ParseState *pstate, List *name, List
*args, bool oldstyle,
List *parameters);
diff --git a/src/include/nodes/nodes.h b/src/include/nodes/nodes.h
index 2bc7a5d..d269e77 100644
--- a/src/include/nodes/nodes.h
+++ b/src/include/nodes/nodes.h
@@ -278,6 +278,7 @@ typedef enum NodeTag
T_PlaceHolderInfo,
T_MinMaxAggInfo,
T_PlannerParamItem,
+ T_StatisticExtInfo,
/*
* TAGS FOR MEMORY NODES (memnodes.h)
@@ -423,6 +424,7 @@ typedef enum NodeTag
T_CreateSubscriptionStmt,
T_AlterSubscriptionStmt,
T_DropSubscriptionStmt,
+ T_CreateStatsStmt,
/*
* TAGS FOR PARSE TREE NODES (parsenodes.h)
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index a44d217..0a7a8d5c 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -644,6 +644,16 @@ typedef struct ColumnDef
int location; /* parse location, or
-1 if none/unknown */
} ColumnDef;
+typedef struct CreateStatsStmt
+{
+ NodeTag type;
+ List *defnames; /* qualified name (list of Value
strings) */
+ RangeVar *relation; /* relation to build statistics on */
+ List *keys; /* String nodes naming
referenced column(s) */
+ bool if_not_exists; /* do nothing if statistics already
exists */
+} CreateStatsStmt;
+
+
/*
* TableLikeClause - CREATE TABLE ( ... LIKE ... ) clause
*/
@@ -1593,6 +1603,7 @@ typedef enum ObjectType
OBJECT_SCHEMA,
OBJECT_SEQUENCE,
OBJECT_SUBSCRIPTION,
+ OBJECT_STATISTICS,
OBJECT_TABCONSTRAINT,
OBJECT_TABLE,
OBJECT_TABLESPACE,
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h
index 05d6f07..5923b5f 100644
--- a/src/include/nodes/relation.h
+++ b/src/include/nodes/relation.h
@@ -525,6 +525,7 @@ typedef struct RelOptInfo
List *lateral_vars; /* LATERAL Vars and PHVs referenced by
rel */
Relids lateral_referencers; /* rels that reference me
laterally */
List *indexlist; /* list of IndexOptInfo */
+ List *statlist; /* list of StatisticExtInfo */
BlockNumber pages; /* size estimates derived from
pg_class */
double tuples;
double allvisfrac;
@@ -664,6 +665,31 @@ typedef struct ForeignKeyOptInfo
List *rinfos[INDEX_MAX_KEYS];
} ForeignKeyOptInfo;
+/*
+ * StatisticExtInfo
+ * Information about extended statistics for planning/optimization
+ *
+ * This contains information about which columns are covered by the
+ * statistics (stakeys), which options were requested while adding the
+ * statistics (*_enabled), and which kinds of statistics were actually
+ * built and are available for the optimizer (*_built).
+ */
+typedef struct StatisticExtInfo
+{
+ NodeTag type;
+
+ Oid statOid; /* OID of the
statistics row */
+ RelOptInfo *rel; /* back-link to index's table */
+
+ /* enabled statistics */
+ bool ndist_enabled; /* ndistinct coefficient enabled */
+
+ /* built/available statistics */
+ bool ndist_built; /* ndistinct coefficient built */
+
+ /* columns in the statistics (attnums) */
+ int2vector *stakeys; /* attnums of the columns covered */
+} StatisticExtInfo;
/*
* EquivalenceClasses
diff --git a/src/include/statistics/common.h b/src/include/statistics/common.h
new file mode 100644
index 0000000..39c62bd
--- /dev/null
+++ b/src/include/statistics/common.h
@@ -0,0 +1,62 @@
+/*-------------------------------------------------------------------------
+ *
+ * common.h
+ * POSTGRES extended statistics internal declarations
+ *
+ * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * IDENTIFICATION
+ * src/include/statistics/common.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef STATISTICS_COMMON_H
+#define STATISTICS_COMMON_H
+
+#include "commands/vacuum.h"
+#include "utils/sortsupport.h"
+
+
+typedef struct
+{
+ Oid eqopr; /* '=' operator for
datatype, if any */
+ Oid eqfunc; /* and associated
function */
+ Oid ltopr; /* '<' operator for
datatype, if any */
+} StdAnalyzeData;
+
+typedef struct
+{
+ Datum value; /* a data value */
+ int tupno; /* position index for
tuple it came from */
+} ScalarItem;
+
+/* multi-sort */
+typedef struct MultiSortSupportData
+{
+ int ndims; /* number of dimensions
supported by the */
+ SortSupportData ssup[1]; /* sort support data for each dimension
*/
+} MultiSortSupportData;
+
+typedef MultiSortSupportData *MultiSortSupport;
+
+typedef struct SortItem
+{
+ Datum *values;
+ bool *isnull;
+} SortItem;
+
+extern MultiSortSupport multi_sort_init(int ndims);
+extern void multi_sort_add_dimension(MultiSortSupport mss, int sortdim,
+ int dim, VacAttrStats
**vacattrstats);
+extern int multi_sort_compare(const void *a, const void *b, void *arg);
+extern int multi_sort_compare_dim(int dim, const SortItem * a,
+ const SortItem * b, MultiSortSupport
mss);
+extern int multi_sort_compare_dims(int start, int end, const SortItem * a,
+ const SortItem * b,
MultiSortSupport mss);
+
+/* comparators, used when constructing extended stats */
+extern int compare_scalars_simple(const void *a, const void *b, void *arg);
+extern int compare_scalars_partition(const void *a, const void *b, void
*arg);
+
+#endif /* STATISTICS_COMMON_H */
diff --git a/src/include/statistics/stats.h b/src/include/statistics/stats.h
new file mode 100644
index 0000000..ed14459
--- /dev/null
+++ b/src/include/statistics/stats.h
@@ -0,0 +1,57 @@
+/*-------------------------------------------------------------------------
+ *
+ * stats.h
+ * Multivariate statistics and selectivity estimation functions.
+ *
+ * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/statistics/stats.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef STATS_H
+#define STATS_H
+
+#include "commands/vacuum.h"
+
+#define STATS_MAX_DIMENSIONS 8 /* max number of attributes */
+
+#define STATS_NDISTINCT_MAGIC 0xA352BFA4 /* marks serialized
bytea */
+#define STATS_NDISTINCT_TYPE_BASIC 1 /* basic MCV list type */
+
+/* Multivariate distinct coefficients. */
+typedef struct MVNDistinctItem
+{
+ double ndistinct;
+ AttrNumber nattrs;
+ AttrNumber *attrs;
+} MVNDistinctItem;
+
+typedef struct MVNDistinctData
+{
+ uint32 magic; /* magic constant marker */
+ uint32 type; /* type of ndistinct (BASIC) */
+ uint32 nitems; /* number of items in the
statistic */
+ MVNDistinctItem items[FLEXIBLE_ARRAY_MEMBER];
+} MVNDistinctData;
+
+typedef MVNDistinctData *MVNDistinct;
+
+extern MVNDistinct load_ext_ndistinct(Oid mvoid);
+
+extern bytea *serialize_ext_ndistinct(MVNDistinct ndistinct);
+
+/* deserialization of stats (serialization is private to analyze) */
+extern MVNDistinct deserialize_ext_ndistinct(bytea *data);
+
+extern MVNDistinct build_ext_ndistinct(double totalrows, int numrows,
HeapTuple *rows,
+ int2vector *attrs, VacAttrStats
**stats);
+
+extern void build_ext_stats(Relation onerel, double totalrows,
+ int numrows, HeapTuple *rows,
+ int natts, VacAttrStats **vacattrstats);
+extern bool stats_are_enabled(HeapTuple htup, char type);
+extern bool stats_are_built(HeapTuple htup, char type);
+
+#endif /* STATS_H */
diff --git a/src/include/utils/acl.h b/src/include/utils/acl.h
index 0d11852..90dac93 100644
--- a/src/include/utils/acl.h
+++ b/src/include/utils/acl.h
@@ -326,6 +326,7 @@ extern bool pg_event_trigger_ownercheck(Oid et_oid, Oid
roleid);
extern bool pg_extension_ownercheck(Oid ext_oid, Oid roleid);
extern bool pg_publication_ownercheck(Oid pub_oid, Oid roleid);
extern bool pg_subscription_ownercheck(Oid sub_oid, Oid roleid);
+extern bool pg_statistics_ownercheck(Oid stat_oid, Oid roleid);
extern bool has_createrole_privilege(Oid roleid);
extern bool has_bypassrls_privilege(Oid roleid);
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index a617a7c..5772804 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -92,6 +92,7 @@ typedef struct RelationData
bool rd_isvalid; /* relcache entry is valid */
char rd_indexvalid; /* state of rd_indexlist: 0 = not
valid, 1 =
* valid, 2 =
temporarily forced */
+ bool rd_statvalid; /* state of rd_statlist: true/false */
/*
* rd_createSubid is the ID of the highest subtransaction the rel has
@@ -136,6 +137,9 @@ typedef struct RelationData
Oid rd_pkindex; /* OID of primary key,
if any */
Oid rd_replidindex; /* OID of replica identity
index, if any */
+ /* data managed by RelationGetStatExtList: */
+ List *rd_statlist; /* list of OIDs of extended stats */
+
/* data managed by RelationGetIndexAttrBitmap: */
Bitmapset *rd_indexattr; /* identifies columns used in indexes */
Bitmapset *rd_keyattr; /* cols that can be ref'd by foreign
keys */
diff --git a/src/include/utils/relcache.h b/src/include/utils/relcache.h
index da36b67..81af3ae 100644
--- a/src/include/utils/relcache.h
+++ b/src/include/utils/relcache.h
@@ -39,6 +39,7 @@ extern void RelationClose(Relation relation);
*/
extern List *RelationGetFKeyList(Relation relation);
extern List *RelationGetIndexList(Relation relation);
+extern List *RelationGetStatExtList(Relation relation);
extern Oid RelationGetOidIndex(Relation relation);
extern Oid RelationGetPrimaryKeyIndex(Relation relation);
extern Oid RelationGetReplicaIndex(Relation relation);
diff --git a/src/include/utils/syscache.h b/src/include/utils/syscache.h
index 66f60d2..048541e 100644
--- a/src/include/utils/syscache.h
+++ b/src/include/utils/syscache.h
@@ -86,6 +86,8 @@ enum SysCacheIdentifier
PUBLICATIONRELMAP,
RULERELNAME,
SEQRELID,
+ STATEXTNAMENSP,
+ STATEXTOID,
STATRELATTINH,
SUBSCRIPTIONOID,
SUBSCRIPTIONNAME,
diff --git a/src/test/regress/expected/object_address.out
b/src/test/regress/expected/object_address.out
index 836773f..07b3701 100644
--- a/src/test/regress/expected/object_address.out
+++ b/src/test/regress/expected/object_address.out
@@ -38,6 +38,7 @@ CREATE TRANSFORM FOR int LANGUAGE SQL (
TO SQL WITH FUNCTION int4recv(internal));
CREATE PUBLICATION addr_pub FOR TABLE addr_nsp.gentable;
CREATE SUBSCRIPTION addr_sub CONNECTION '' PUBLICATION bar WITH (DISABLED,
NOCREATE SLOT);
+CREATE STATISTICS addr_nsp.gentable_stat ON (a,b) FROM addr_nsp.gentable;
-- test some error cases
SELECT pg_get_object_address('stone', '{}', '{}');
ERROR: unrecognized object type "stone"
@@ -399,7 +400,8 @@ WITH objects (type, name, args) AS (VALUES
('access method', '{btree}', '{}'),
('publication', '{addr_pub}', '{}'),
('publication relation', '{addr_nsp,
gentable}', '{addr_pub}'),
- ('subscription', '{addr_sub}', '{}')
+ ('subscription', '{addr_sub}', '{}'),
+ ('statistics', '{addr_nsp, gentable_stat}',
'{}')
)
SELECT (pg_identify_object(addr1.classid, addr1.objid, addr1.objsubid)).*,
-- test roundtrip through pg_identify_object_as_address
@@ -447,6 +449,7 @@ SELECT (pg_identify_object(addr1.classid, addr1.objid,
addr1.objsubid)).*,
trigger | | | t on
addr_nsp.gentable | t
operator family | pg_catalog | integer_ops |
pg_catalog.integer_ops USING btree | t
policy | | | genpol on
addr_nsp.gentable | t
+ statistics | addr_nsp | gentable_stat |
addr_nsp.gentable_stat | t
collation | pg_catalog | "default" |
pg_catalog."default" | t
transform | | | for integer on
language sql | t
text search dictionary | addr_nsp | addr_ts_dict |
addr_nsp.addr_ts_dict | t
@@ -456,7 +459,7 @@ SELECT (pg_identify_object(addr1.classid, addr1.objid,
addr1.objsubid)).*,
subscription | | addr_sub | addr_sub
| t
publication | | addr_pub | addr_pub
| t
publication relation | | | gentable in
publication addr_pub | t
-(45 rows)
+(46 rows)
---
--- Cleanup resources
diff --git a/src/test/regress/expected/opr_sanity.out
b/src/test/regress/expected/opr_sanity.out
index 0bcec13..9a26205 100644
--- a/src/test/regress/expected/opr_sanity.out
+++ b/src/test/regress/expected/opr_sanity.out
@@ -817,11 +817,12 @@ WHERE c.castmethod = 'b' AND
text | character | 0 | i
character varying | character | 0 | i
pg_node_tree | text | 0 | i
+ pg_ndistinct | bytea | 0 | i
cidr | inet | 0 | i
xml | text | 0 | a
xml | character varying | 0 | a
xml | character | 0 | a
-(7 rows)
+(8 rows)
-- **************** pg_conversion ****************
-- Look for illegal values in pg_conversion fields.
diff --git a/src/test/regress/expected/rules.out
b/src/test/regress/expected/rules.out
index bd13ae6..d4b2158 100644
--- a/src/test/regress/expected/rules.out
+++ b/src/test/regress/expected/rules.out
@@ -2160,6 +2160,14 @@ pg_stats| SELECT n.nspname AS schemaname,
JOIN pg_attribute a ON (((c.oid = a.attrelid) AND (a.attnum =
s.staattnum))))
LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace)))
WHERE ((NOT a.attisdropped) AND has_column_privilege(c.oid, a.attnum,
'select'::text) AND ((c.relrowsecurity = false) OR (NOT
row_security_active(c.oid))));
+pg_stats_ext| SELECT n.nspname AS schemaname,
+ c.relname AS tablename,
+ s.staname,
+ s.stakeys AS attnums,
+ length((s.standistinct)::text) AS ndistbytes
+ FROM ((pg_statistic_ext s
+ JOIN pg_class c ON ((c.oid = s.starelid)))
+ LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace)));
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/sanity_check.out
b/src/test/regress/expected/sanity_check.out
index b5eff55..9edba4f 100644
--- a/src/test/regress/expected/sanity_check.out
+++ b/src/test/regress/expected/sanity_check.out
@@ -142,6 +142,7 @@ pg_shdepend|t
pg_shdescription|t
pg_shseclabel|t
pg_statistic|t
+pg_statistic_ext|t
pg_subscription|t
pg_tablespace|t
pg_transform|t
diff --git a/src/test/regress/expected/stats_ext.out
b/src/test/regress/expected/stats_ext.out
new file mode 100644
index 0000000..77ce1f1
--- /dev/null
+++ b/src/test/regress/expected/stats_ext.out
@@ -0,0 +1,117 @@
+-- data type passed by value
+CREATE TABLE ndistinct (
+ a INT,
+ b INT,
+ c INT,
+ d INT
+);
+-- unknown column
+CREATE STATISTICS s10 ON (unknown_column) FROM ndistinct;
+ERROR: column "unknown_column" referenced in statistics does not exist
+-- single column
+CREATE STATISTICS s10 ON (a) FROM ndistinct;
+ERROR: statistics require at least 2 columns
+-- single column, duplicated
+CREATE STATISTICS s10 ON (a,a) FROM ndistinct;
+ERROR: duplicate column name in statistics definition
+-- two columns, one duplicated
+CREATE STATISTICS s10 ON (a, a, b) FROM ndistinct;
+ERROR: duplicate column name in statistics definition
+-- correct command
+CREATE STATISTICS s10 ON (a, b, c) FROM ndistinct;
+-- perfectly correlated groups
+INSERT INTO ndistinct
+ SELECT i/100, i/100, i/100 FROM generate_series(1,10000) s(i);
+ANALYZE ndistinct;
+SELECT staenabled, standistinct
+ FROM pg_statistic_ext WHERE starelid = 'ndistinct'::regclass;
+ staenabled | standistinct
+------------+-------------------------------------------------------------------------------------
+ {d} | [{0, 1, 101.000000}, {0, 2, 101.000000}, {1, 2, 101.000000}, {0,
1, 2, 101.000000}]
+(1 row)
+
+EXPLAIN (COSTS off)
+ SELECT COUNT(*) FROM ndistinct GROUP BY a, b;
+ QUERY PLAN
+-----------------------------
+ HashAggregate
+ Group Key: a, b
+ -> Seq Scan on ndistinct
+(3 rows)
+
+EXPLAIN (COSTS off)
+ SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c;
+ QUERY PLAN
+-----------------------------
+ HashAggregate
+ Group Key: a, b, c
+ -> Seq Scan on ndistinct
+(3 rows)
+
+EXPLAIN (COSTS off)
+ SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c, d;
+ QUERY PLAN
+-----------------------------
+ HashAggregate
+ Group Key: a, b, c, d
+ -> Seq Scan on ndistinct
+(3 rows)
+
+TRUNCATE TABLE ndistinct;
+-- partially correlated groups
+INSERT INTO ndistinct
+ SELECT i/50, i/100, i/200 FROM generate_series(1,10000) s(i);
+ANALYZE ndistinct;
+SELECT staenabled, standistinct
+ FROM pg_statistic_ext WHERE starelid = 'ndistinct'::regclass;
+ staenabled | standistinct
+------------+-------------------------------------------------------------------------------------
+ {d} | [{0, 1, 201.000000}, {0, 2, 201.000000}, {1, 2, 101.000000}, {0,
1, 2, 201.000000}]
+(1 row)
+
+EXPLAIN
+ SELECT COUNT(*) FROM ndistinct GROUP BY a, b;
+ QUERY PLAN
+---------------------------------------------------------------------
+ HashAggregate (cost=230.00..232.01 rows=201 width=16)
+ Group Key: a, b
+ -> Seq Scan on ndistinct (cost=0.00..155.00 rows=10000 width=8)
+(3 rows)
+
+EXPLAIN
+ SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c;
+ QUERY PLAN
+----------------------------------------------------------------------
+ HashAggregate (cost=255.00..257.01 rows=201 width=20)
+ Group Key: a, b, c
+ -> Seq Scan on ndistinct (cost=0.00..155.00 rows=10000 width=12)
+(3 rows)
+
+EXPLAIN
+ SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c, d;
+ QUERY PLAN
+----------------------------------------------------------------------
+ HashAggregate (cost=280.00..290.00 rows=1000 width=24)
+ Group Key: a, b, c, d
+ -> Seq Scan on ndistinct (cost=0.00..155.00 rows=10000 width=16)
+(3 rows)
+
+EXPLAIN
+ SELECT COUNT(*) FROM ndistinct GROUP BY b, c, d;
+ QUERY PLAN
+----------------------------------------------------------------------
+ HashAggregate (cost=255.00..265.00 rows=1000 width=20)
+ Group Key: b, c, d
+ -> Seq Scan on ndistinct (cost=0.00..155.00 rows=10000 width=12)
+(3 rows)
+
+EXPLAIN
+ SELECT COUNT(*) FROM ndistinct GROUP BY a, d;
+ QUERY PLAN
+---------------------------------------------------------------------
+ HashAggregate (cost=230.00..240.00 rows=1000 width=16)
+ Group Key: a, d
+ -> Seq Scan on ndistinct (cost=0.00..155.00 rows=10000 width=8)
+(3 rows)
+
+DROP TABLE ndistinct;
diff --git a/src/test/regress/expected/type_sanity.out
b/src/test/regress/expected/type_sanity.out
index 8d75bbf..f6b799a 100644
--- a/src/test/regress/expected/type_sanity.out
+++ b/src/test/regress/expected/type_sanity.out
@@ -59,7 +59,7 @@ WHERE (p1.typtype = 'c' AND p1.typrelid = 0) OR
-- Look for types that should have an array type according to their typtype,
-- but don't. We exclude composites here because we have not bothered to
-- make array types corresponding to the system catalogs' rowtypes.
--- NOTE: as of v10, this check finds pg_node_tree and smgr.
+-- NOTE: as of v10, this check finds pg_node_tree, pg_ndistinct, smgr.
SELECT p1.oid, p1.typname
FROM pg_type as p1
WHERE p1.typtype not in ('c','d','p') AND p1.typname NOT LIKE E'\\_%'
@@ -67,11 +67,12 @@ WHERE p1.typtype not in ('c','d','p') AND p1.typname NOT
LIKE E'\\_%'
(SELECT 1 FROM pg_type as p2
WHERE p2.typname = ('_' || p1.typname)::name AND
p2.typelem = p1.oid and p1.typarray = p2.oid);
- oid | typname
------+--------------
- 194 | pg_node_tree
- 210 | smgr
-(2 rows)
+ oid | typname
+------+--------------
+ 194 | pg_node_tree
+ 3353 | pg_ndistinct
+ 210 | smgr
+(3 rows)
-- Make sure typarray points to a varlena array type of our own base
SELECT p1.oid, p1.typname as basetype, p2.typname as arraytype,
diff --git a/src/test/regress/parallel_schedule
b/src/test/regress/parallel_schedule
index 9f38349..a8ebf93 100644
--- a/src/test/regress/parallel_schedule
+++ b/src/test/regress/parallel_schedule
@@ -89,7 +89,7 @@ test: brin gin gist spgist privileges init_privs
security_label collate matview
# ----------
# Another group of parallel tests
# ----------
-test: alter_generic alter_operator misc psql async dbsize misc_functions
sysviews tsrf
+test: alter_generic alter_operator misc psql async dbsize misc_functions
sysviews tsrf stats_ext
# rules cannot run concurrently with any test that creates a view
test: rules psql_crosstab amutils
diff --git a/src/test/regress/serial_schedule b/src/test/regress/serial_schedule
index 2987b24..bff9432 100644
--- a/src/test/regress/serial_schedule
+++ b/src/test/regress/serial_schedule
@@ -128,6 +128,7 @@ test: dbsize
test: misc_functions
test: sysviews
test: tsrf
+test: stats_ext
test: rules
test: psql_crosstab
test: select_parallel
diff --git a/src/test/regress/sql/object_address.sql
b/src/test/regress/sql/object_address.sql
index 0ace4dd..4e34185 100644
--- a/src/test/regress/sql/object_address.sql
+++ b/src/test/regress/sql/object_address.sql
@@ -41,6 +41,7 @@ CREATE TRANSFORM FOR int LANGUAGE SQL (
TO SQL WITH FUNCTION int4recv(internal));
CREATE PUBLICATION addr_pub FOR TABLE addr_nsp.gentable;
CREATE SUBSCRIPTION addr_sub CONNECTION '' PUBLICATION bar WITH (DISABLED,
NOCREATE SLOT);
+CREATE STATISTICS addr_nsp.gentable_stat ON (a,b) FROM addr_nsp.gentable;
-- test some error cases
SELECT pg_get_object_address('stone', '{}', '{}');
@@ -179,7 +180,8 @@ WITH objects (type, name, args) AS (VALUES
('access method', '{btree}', '{}'),
('publication', '{addr_pub}', '{}'),
('publication relation', '{addr_nsp,
gentable}', '{addr_pub}'),
- ('subscription', '{addr_sub}', '{}')
+ ('subscription', '{addr_sub}', '{}'),
+ ('statistics', '{addr_nsp, gentable_stat}',
'{}')
)
SELECT (pg_identify_object(addr1.classid, addr1.objid, addr1.objsubid)).*,
-- test roundtrip through pg_identify_object_as_address
diff --git a/src/test/regress/sql/stats_ext.sql
b/src/test/regress/sql/stats_ext.sql
new file mode 100644
index 0000000..6381157
--- /dev/null
+++ b/src/test/regress/sql/stats_ext.sql
@@ -0,0 +1,75 @@
+-- Generic extended statistics support
+CREATE TABLE ab1 (a int, b int);
+CREATE STATISTICS ab1_a_b_stats ON (a, b) FROM ab1;
+ALTER TABLE ab1 DROP COLUMN a;
+DROP TABLE ab1;
+
+
+-- data type passed by value
+CREATE TABLE ndistinct (
+ a INT,
+ b INT,
+ c INT,
+ d INT
+);
+
+-- unknown column
+CREATE STATISTICS s10 ON (unknown_column) FROM ndistinct;
+
+-- single column
+CREATE STATISTICS s10 ON (a) FROM ndistinct;
+
+-- single column, duplicated
+CREATE STATISTICS s10 ON (a,a) FROM ndistinct;
+
+-- two columns, one duplicated
+CREATE STATISTICS s10 ON (a, a, b) FROM ndistinct;
+
+-- correct command
+CREATE STATISTICS s10 ON (a, b, c) FROM ndistinct;
+
+-- perfectly correlated groups
+INSERT INTO ndistinct
+ SELECT i/100, i/100, i/100 FROM generate_series(1,10000) s(i);
+
+ANALYZE ndistinct;
+
+SELECT staenabled, standistinct
+ FROM pg_statistic_ext WHERE starelid = 'ndistinct'::regclass;
+
+EXPLAIN (COSTS off)
+ SELECT COUNT(*) FROM ndistinct GROUP BY a, b;
+
+EXPLAIN (COSTS off)
+ SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c;
+
+EXPLAIN (COSTS off)
+ SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c, d;
+
+TRUNCATE TABLE ndistinct;
+
+-- partially correlated groups
+INSERT INTO ndistinct
+ SELECT i/50, i/100, i/200 FROM generate_series(1,10000) s(i);
+
+ANALYZE ndistinct;
+
+SELECT staenabled, standistinct
+ FROM pg_statistic_ext WHERE starelid = 'ndistinct'::regclass;
+
+EXPLAIN
+ SELECT COUNT(*) FROM ndistinct GROUP BY a, b;
+
+EXPLAIN
+ SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c;
+
+EXPLAIN
+ SELECT COUNT(*) FROM ndistinct GROUP BY a, b, c, d;
+
+EXPLAIN
+ SELECT COUNT(*) FROM ndistinct GROUP BY b, c, d;
+
+EXPLAIN
+ SELECT COUNT(*) FROM ndistinct GROUP BY a, d;
+
+DROP TABLE ndistinct;
diff --git a/src/test/regress/sql/type_sanity.sql
b/src/test/regress/sql/type_sanity.sql
index 0a31249..4c65814 100644
--- a/src/test/regress/sql/type_sanity.sql
+++ b/src/test/regress/sql/type_sanity.sql
@@ -53,7 +53,7 @@ WHERE (p1.typtype = 'c' AND p1.typrelid = 0) OR
-- Look for types that should have an array type according to their typtype,
-- but don't. We exclude composites here because we have not bothered to
-- make array types corresponding to the system catalogs' rowtypes.
--- NOTE: as of v10, this check finds pg_node_tree and smgr.
+-- NOTE: as of v10, this check finds pg_node_tree, pg_ndistinct, smgr.
SELECT p1.oid, p1.typname
FROM pg_type as p1
--
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