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Rework the pg_statistic_ext catalog 

Since extended statistic got introduced in PostgreSQL 10, there was a
single catalog pg_statistic_ext storing both the definitions and built
statistic.  That's however problematic when a user is supposed to have
access only to the definitions, but not to user data.

Consider for example pg_dump on a database with RLS enabled - if the
pg_statistic_ext catalog respects RLS (which it should, if it contains
user data), pg_dump would not see any records and the result would not
define any extended statistics.  That would be a surprising behavior.

Until now this was not a pressing issue, because the existing types of
extended statistic (functional dependencies and ndistinct coefficients)
do not include any user data directly.  This changed with introduction
of MCV lists, which do include most common combinations of values.

The easiest way to fix this is to split the pg_statistic_ext catalog
into two - one for definitions, one for the built statistic values.
The new catalog is called pg_statistic_ext_data, and we're maintaining
a 1:1 relationship with the old catalog - either there are matching
records in both catalogs, or neither of them.

Bumped CATVERSION due to changing system catalog definitions.

Author: Dean Rasheed, with improvements by me
Reviewed-by: Dean Rasheed, John Naylor
Discussion: https://postgr.es/m/CAEZATCUhT9rt7Ui%3DVdx4N%3D%3DVV5XOK5dsXfnGgVOz_JhAicB%3DZA%40mail.gmail.com
This commit is contained in:
Tomas Vondra 2019-06-13 17:19:21 +02:00
parent e3846a00c2
commit 6cbfb784c3
25 changed files with 337 additions and 118 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

70
doc/src/sgml/catalogs.sgml
View File

@ -297,7 +297,12 @@
<row>
<entry><link linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link></entry>
<entry>extended planner statistics</entry>
<entry>extended planner statistics (definition)</entry>
</row>
<row>
<entry><link linkend="catalog-pg-statistic-ext-data"><structname>pg_statistic_ext_data</structname></link></entry>
<entry>extended planner statistics (built statistics)</entry>
</row>
<row>
@ -6506,7 +6511,7 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
<para>
The catalog <structname>pg_statistic_ext</structname>
holds extended planner statistics.
holds definitions of extended planner statistics.
Each row in this catalog corresponds to a <firstterm>statistics object</firstterm>
created with <xref linkend="sql-createstatistics"/>.
</para>
@ -6581,8 +6586,57 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
</entry>
</row>
</tbody>
</tgroup>
</table>
<para>
The <structfield>stxkind</structfield> field is filled at creation of the
statistics object, indicating which statistic type(s) are desired. The
statistics (once computed by <command>ANALYZE</command>) are stored in
<link linkend="catalog-pg-statistic-ext-data"><structname>pg_statistic_ext_data</structname></link>
catalog.
</para>
</sect1>
<sect1 id="catalog-pg-statistic-ext-data">
<title><structname>pg_statistic_ext_data</structname></title>
<indexterm zone="catalog-pg-statistic-ext">
<primary>pg_statistic_ext_data</primary>
</indexterm>
<para>
The catalog <structname>pg_statistic_ext_data</structname>
holds data for extended planner statistics defined in <structname>pg_statistic_ext</structname>.
Each row in this catalog corresponds to a <firstterm>statistics object</firstterm>
created with <xref linkend="sql-createstatistics"/>.
</para>
<table>
<title><structname>pg_statistic_ext_data</structname> Columns</title>
<tgroup cols="4">
<thead>
<row>
<entry><structfield>stxndistinct</structfield></entry>
<entry>Name</entry>
<entry>Type</entry>
<entry>References</entry>
<entry>Description</entry>
</row>
</thead>
<tbody>
<row>
<entry><structfield>stxoid</structfield></entry>
<entry><type>oid</type></entry>
<entry><literal><link linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link>.oid</literal></entry>
<entry>Extended statistic containing the definition for this data.</entry>
</row>
<row>
<entry><structfield>stxdndistinct</structfield></entry>
<entry><type>pg_ndistinct</type></entry>
<entry></entry>
<entry>
@ -6591,7 +6645,7 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
</row>
<row>
<entry><structfield>stxdependencies</structfield></entry>
<entry><structfield>stxddependencies</structfield></entry>
<entry><type>pg_dependencies</type></entry>
<entry></entry>
<entry>
@ -6601,7 +6655,7 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
</row>
<row>
<entry><structfield>stxmcv</structfield></entry>
<entry><structfield>stxdmcv</structfield></entry>
<entry><type>pg_mcv_list</type></entry>
<entry></entry>
<entry>
@ -6614,12 +6668,6 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
</tgroup>
</table>
<para>
The <structfield>stxkind</structfield> field is filled at creation of the
statistics object, indicating which statistic type(s) are desired.
The fields after it are initially NULL and are filled only when the
corresponding statistic has been computed by <command>ANALYZE</command>.
</para>
</sect1>
<sect1 id="catalog-pg-subscription">

6
doc/src/sgml/func.sgml
View File

@ -22427,12 +22427,12 @@ CREATE EVENT TRIGGER test_table_rewrite_oid
The <function>pg_mcv_list_items</function> function can be used like this:
<programlisting>
SELECT m.* FROM pg_statistic_ext,
pg_mcv_list_items(stxmcv) m WHERE stxname = 'stts';
SELECT m.* FROM pg_statistic_ext join pg_statistic_ext_data on (oid = stxoid),
pg_mcv_list_items(stxdmcv) m WHERE stxname = 'stts';
</programlisting>
Values of the <type>pg_mcv_list</type> can be obtained only from the
<literal>pg_statistic_ext.stxmcv</literal> column.
<literal>pg_statistic_ext_data.stxdmcv</literal> column.
</para>
</sect2>

20
doc/src/sgml/perform.sgml
View File

@ -1076,6 +1076,10 @@ WHERE tablename = 'road';
<primary>pg_statistic_ext</primary>
</indexterm>
<indexterm>
<primary>pg_statistic_ext_data</primary>
</indexterm>
<para>
It is common to see slow queries running bad execution plans because
multiple columns used in the query clauses are correlated.
@ -1104,7 +1108,7 @@ WHERE tablename = 'road';
interest in the statistics. Actual data collection is performed
by <command>ANALYZE</command> (either a manual command, or background
auto-analyze). The collected values can be examined in the
<link linkend="catalog-pg-statistic-ext"><structname>pg_statistic_ext</structname></link>
<link linkend="catalog-pg-statistic-ext-data"><structname>pg_statistic_ext_data</structname></link>
catalog.
</para>
@ -1172,10 +1176,10 @@ CREATE STATISTICS stts (dependencies) ON zip, city FROM zipcodes;
ANALYZE zipcodes;
SELECT stxname, stxkeys, stxdependencies
FROM pg_statistic_ext
SELECT stxname, stxkeys, stxddependencies
FROM pg_statistic_ext join pg_statistic_ext_data on (oid = stxoid)
WHERE stxname = 'stts';
stxname | stxkeys | stxdependencies
stxname | stxkeys | stxddependencies
---------+---------+------------------------------------------
stts | 1 5 | {"1 => 5": 1.000000, "5 => 1": 0.423130}
(1 row)
@ -1262,8 +1266,8 @@ CREATE STATISTICS stts2 (ndistinct) ON zip, state, city FROM zipcodes;
ANALYZE zipcodes;
SELECT stxkeys AS k, stxndistinct AS nd
FROM pg_statistic_ext
SELECT stxkeys AS k, stxdndistinct AS nd
FROM pg_statistic_ext join pg_statistic_ext_data on (oid = stxoid)
WHERE stxname = 'stts2';
-[ RECORD 1 ]--------------------------------------------------------
k | 1 2 5
@ -1317,8 +1321,8 @@ CREATE STATISTICS stts3 (mcv) ON state, city FROM zipcodes;
ANALYZE zipcodes;
SELECT m.* FROM pg_statistic_ext,
pg_mcv_list_items(stxmcv) m WHERE stxname = 'stts3';
SELECT m.* FROM pg_statistic_ext join pg_statistic_ext_data on (oid = stxoid),
pg_mcv_list_items(stxdmcv) m WHERE stxname = 'stts3';
index | values | nulls | frequency | base_frequency
-------+------------------------+-------+-----------+----------------

4
doc/src/sgml/planstats.sgml
View File

@ -635,8 +635,8 @@ EXPLAIN (ANALYZE, TIMING OFF) SELECT * FROM t WHERE a = 1 AND b = 1;
<function>pg_mcv_list_items</function> set-returning function.
<programlisting>
SELECT m.* FROM pg_statistic_ext,
pg_mcv_list_items(stxmcv) m WHERE stxname = 'stts2';
SELECT m.* FROM pg_statistic_ext join pg_statistic_ext_data on (oid = stxoid),
pg_mcv_list_items(stxdmcv) m WHERE stxname = 'stts2';
index | values | nulls | frequency | base_frequency
-------+----------+-------+-----------+----------------
0 | {0, 0} | {f,f} | 0.01 | 0.0001

2
src/backend/catalog/Makefile
View File

@ -34,7 +34,7 @@ CATALOG_HEADERS := \
pg_attrdef.h pg_constraint.h pg_inherits.h pg_index.h pg_operator.h \
pg_opfamily.h pg_opclass.h pg_am.h pg_amop.h pg_amproc.h \
pg_language.h pg_largeobject_metadata.h pg_largeobject.h pg_aggregate.h \
pg_statistic_ext.h \
pg_statistic_ext.h pg_statistic_ext_data.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 \

73
src/backend/commands/statscmds.c
View File

@ -23,6 +23,7 @@
#include "catalog/namespace.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_statistic_ext.h"
#include "catalog/pg_statistic_ext_data.h"
#include "commands/comment.h"
#include "commands/defrem.h"
#include "miscadmin.h"
@ -67,8 +68,11 @@ CreateStatistics(CreateStatsStmt *stmt)
HeapTuple htup;
Datum values[Natts_pg_statistic_ext];
bool nulls[Natts_pg_statistic_ext];
Datum datavalues[Natts_pg_statistic_ext_data];
bool datanulls[Natts_pg_statistic_ext_data];
int2vector *stxkeys;
Relation statrel;
Relation datarel;
Relation rel = NULL;
Oid relid;
ObjectAddress parentobject,
@ -336,11 +340,6 @@ CreateStatistics(CreateStatsStmt *stmt)
values[Anum_pg_statistic_ext_stxkeys - 1] = PointerGetDatum(stxkeys);
values[Anum_pg_statistic_ext_stxkind - 1] = PointerGetDatum(stxkind);
/* no statistics built yet */
nulls[Anum_pg_statistic_ext_stxndistinct - 1] = true;
nulls[Anum_pg_statistic_ext_stxdependencies - 1] = true;
nulls[Anum_pg_statistic_ext_stxmcv - 1] = true;
/* insert it into pg_statistic_ext */
htup = heap_form_tuple(statrel->rd_att, values, nulls);
CatalogTupleInsert(statrel, htup);
@ -348,6 +347,29 @@ CreateStatistics(CreateStatsStmt *stmt)
relation_close(statrel, RowExclusiveLock);
/*
* Also build the pg_statistic_ext_data tuple, to hold the actual
* statistics data.
*/
datarel = table_open(StatisticExtDataRelationId, RowExclusiveLock);
memset(datavalues, 0, sizeof(datavalues));
memset(datanulls, false, sizeof(datanulls));
datavalues[Anum_pg_statistic_ext_data_stxoid - 1] = ObjectIdGetDatum(statoid);
/* no statistics built yet */
datanulls[Anum_pg_statistic_ext_data_stxdndistinct - 1] = true;
datanulls[Anum_pg_statistic_ext_data_stxddependencies - 1] = true;
datanulls[Anum_pg_statistic_ext_data_stxdmcv - 1] = true;
/* insert it into pg_statistic_ext_data */
htup = heap_form_tuple(datarel->rd_att, datavalues, datanulls);
CatalogTupleInsert(datarel, htup);
heap_freetuple(htup);
relation_close(datarel, RowExclusiveLock);
/*
* Invalidate relcache so that others see the new statistics object.
*/
@ -403,6 +425,23 @@ RemoveStatisticsById(Oid statsOid)
Form_pg_statistic_ext statext;
Oid relid;
/*
* First delete the pg_statistic_ext_data tuple holding the actual
* statistical data.
*/
relation = table_open(StatisticExtDataRelationId, RowExclusiveLock);
tup = SearchSysCache1(STATEXTDATASTXOID, ObjectIdGetDatum(statsOid));
if (!HeapTupleIsValid(tup)) /* should not happen */
elog(ERROR, "cache lookup failed for statistics data %u", statsOid);
CatalogTupleDelete(relation, &tup->t_self);
ReleaseSysCache(tup);
table_close(relation, RowExclusiveLock);
/*
* Delete the pg_statistic_ext tuple. Also send out a cache inval on the
* associated table, so that dependent plans will be rebuilt.
@ -431,8 +470,8 @@ RemoveStatisticsById(Oid statsOid)
*
* This could throw an error if the type change can't be supported.
* If it can be supported, but the stats must be recomputed, a likely choice
* would be to set the relevant column(s) of the pg_statistic_ext tuple to
* null until the next ANALYZE. (Note that the type change hasn't actually
* would be to set the relevant column(s) of the pg_statistic_ext_data tuple
* to null until the next ANALYZE. (Note that the type change hasn't actually
* happened yet, so one option that's *not* on the table is to recompute
* immediately.)
*
@ -456,11 +495,11 @@ UpdateStatisticsForTypeChange(Oid statsOid, Oid relationOid, int attnum,
Relation rel;
Datum values[Natts_pg_statistic_ext];
bool nulls[Natts_pg_statistic_ext];
bool replaces[Natts_pg_statistic_ext];
Datum values[Natts_pg_statistic_ext_data];
bool nulls[Natts_pg_statistic_ext_data];
bool replaces[Natts_pg_statistic_ext_data];
oldtup = SearchSysCache1(STATEXTOID, ObjectIdGetDatum(statsOid));
oldtup = SearchSysCache1(STATEXTDATASTXOID, ObjectIdGetDatum(statsOid));
if (!HeapTupleIsValid(oldtup))
elog(ERROR, "cache lookup failed for statistics object %u", statsOid);
@ -479,14 +518,14 @@ UpdateStatisticsForTypeChange(Oid statsOid, Oid relationOid, int attnum,
* OK, we need to reset some statistics. So let's build the new tuple,
* replacing the affected statistics types with NULL.
*/
memset(nulls, 0, Natts_pg_statistic_ext * sizeof(bool));
memset(replaces, 0, Natts_pg_statistic_ext * sizeof(bool));
memset(values, 0, Natts_pg_statistic_ext * sizeof(Datum));
memset(nulls, 0, Natts_pg_statistic_ext_data * sizeof(bool));
memset(replaces, 0, Natts_pg_statistic_ext_data * sizeof(bool));
memset(values, 0, Natts_pg_statistic_ext_data * sizeof(Datum));
replaces[Anum_pg_statistic_ext_stxmcv - 1] = true;
nulls[Anum_pg_statistic_ext_stxmcv - 1] = true;
replaces[Anum_pg_statistic_ext_data_stxdmcv - 1] = true;
nulls[Anum_pg_statistic_ext_data_stxdmcv - 1] = true;
rel = heap_open(StatisticExtRelationId, RowExclusiveLock);
rel = heap_open(StatisticExtDataRelationId, RowExclusiveLock);
/* replace the old tuple */
stup = heap_modify_tuple(oldtup,

12
src/backend/optimizer/util/plancat.c
View File

@ -1308,6 +1308,7 @@ get_relation_statistics(RelOptInfo *rel, Relation relation)
Oid statOid = lfirst_oid(l);
Form_pg_statistic_ext staForm;
HeapTuple htup;
HeapTuple dtup;
Bitmapset *keys = NULL;
int i;
@ -1316,6 +1317,10 @@ get_relation_statistics(RelOptInfo *rel, Relation relation)
elog(ERROR, "cache lookup failed for statistics object %u", statOid);
staForm = (Form_pg_statistic_ext) GETSTRUCT(htup);
dtup = SearchSysCache1(STATEXTDATASTXOID, ObjectIdGetDatum(statOid));
if (!HeapTupleIsValid(dtup))
elog(ERROR, "cache lookup failed for statistics object %u", statOid);
/*
* First, build the array of columns covered. This is ultimately
* wasted if no stats within the object have actually been built, but
@ -1325,7 +1330,7 @@ get_relation_statistics(RelOptInfo *rel, Relation relation)
keys = bms_add_member(keys, staForm->stxkeys.values[i]);
/* add one StatisticExtInfo for each kind built */
if (statext_is_kind_built(htup, STATS_EXT_NDISTINCT))
if (statext_is_kind_built(dtup, STATS_EXT_NDISTINCT))
{
StatisticExtInfo *info = makeNode(StatisticExtInfo);
@ -1337,7 +1342,7 @@ get_relation_statistics(RelOptInfo *rel, Relation relation)
stainfos = lcons(info, stainfos);
}
if (statext_is_kind_built(htup, STATS_EXT_DEPENDENCIES))
if (statext_is_kind_built(dtup, STATS_EXT_DEPENDENCIES))
{
StatisticExtInfo *info = makeNode(StatisticExtInfo);
@ -1349,7 +1354,7 @@ get_relation_statistics(RelOptInfo *rel, Relation relation)
stainfos = lcons(info, stainfos);
}
if (statext_is_kind_built(htup, STATS_EXT_MCV))
if (statext_is_kind_built(dtup, STATS_EXT_MCV))
{
StatisticExtInfo *info = makeNode(StatisticExtInfo);
@ -1362,6 +1367,7 @@ get_relation_statistics(RelOptInfo *rel, Relation relation)
}
ReleaseSysCache(htup);
ReleaseSysCache(dtup);
bms_free(keys);
}

9
src/backend/statistics/README.mcv
View File

@ -86,11 +86,14 @@ So instead the MCV lists are stored in a custom data type (pg_mcv_list),
which however makes it more difficult to inspect the contents. To make that
easier, there's a SRF returning detailed information about the MCV lists.
SELECT m.* FROM pg_statistic_ext,
pg_mcv_list_items(stxmcv) m WHERE stxname = 'stts2';
SELECT m.* FROM pg_statistic_ext s,
pg_statistic_ext_data d,
pg_mcv_list_items(stxdmcv) m
WHERE s.stxname = 'stts2'
AND d.stxoid = s.oid;
It accepts one parameter - a pg_mcv_list value (which can only be obtained
from pg_statistic_ext catalog, to defend against malicious input), and
from pg_statistic_ext_data catalog, to defend against malicious input), and
returns these columns:
- item index (0, ..., (nitems-1))

7
src/backend/statistics/dependencies.c
View File

@ -17,6 +17,7 @@
#include "access/sysattr.h"
#include "catalog/pg_operator.h"
#include "catalog/pg_statistic_ext.h"
#include "catalog/pg_statistic_ext_data.h"
#include "lib/stringinfo.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/clauses.h"
@ -637,12 +638,12 @@ statext_dependencies_load(Oid mvoid)
Datum deps;
HeapTuple htup;
htup = SearchSysCache1(STATEXTOID, ObjectIdGetDatum(mvoid));
htup = SearchSysCache1(STATEXTDATASTXOID, ObjectIdGetDatum(mvoid));
if (!HeapTupleIsValid(htup))
elog(ERROR, "cache lookup failed for statistics object %u", mvoid);
deps = SysCacheGetAttr(STATEXTOID, htup,
Anum_pg_statistic_ext_stxdependencies, &isnull);
deps = SysCacheGetAttr(STATEXTDATASTXOID, htup,
Anum_pg_statistic_ext_data_stxddependencies, &isnull);
if (isnull)
elog(ERROR,
"requested statistic kind \"%c\" is not yet built for statistics object %u",

61
src/backend/statistics/extended_stats.c
View File

@ -23,6 +23,7 @@
#include "catalog/indexing.h"
#include "catalog/pg_collation.h"
#include "catalog/pg_statistic_ext.h"
#include "catalog/pg_statistic_ext_data.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/clauses.h"
#include "optimizer/optimizer.h"
@ -65,9 +66,9 @@ typedef struct StatExtEntry
static List *fetch_statentries_for_relation(Relation pg_statext, Oid relid);
static VacAttrStats **lookup_var_attr_stats(Relation rel, Bitmapset *attrs,
int nvacatts, VacAttrStats **vacatts);
static void statext_store(Relation pg_stext, Oid relid,
static void statext_store(Oid relid,
MVNDistinct *ndistinct, MVDependencies *dependencies,
MCVList *mcvlist, VacAttrStats **stats);
MCVList *mcv, VacAttrStats **stats);
/*
@ -145,7 +146,7 @@ BuildRelationExtStatistics(Relation onerel, double totalrows,
}
/* store the statistics in the catalog */
statext_store(pg_stext, stat->statOid, ndistinct, dependencies, mcv, stats);
statext_store(stat->statOid, ndistinct, dependencies, mcv, stats);
}
table_close(pg_stext, RowExclusiveLock);
@ -156,7 +157,7 @@ BuildRelationExtStatistics(Relation onerel, double totalrows,
/*
* statext_is_kind_built
* Is this stat kind built in the given pg_statistic_ext tuple?
* Is this stat kind built in the given pg_statistic_ext_data tuple?
*/
bool
statext_is_kind_built(HeapTuple htup, char type)
@ -166,15 +167,15 @@ statext_is_kind_built(HeapTuple htup, char type)
switch (type)
{
case STATS_EXT_NDISTINCT:
attnum = Anum_pg_statistic_ext_stxndistinct;
attnum = Anum_pg_statistic_ext_data_stxdndistinct;
break;
case STATS_EXT_DEPENDENCIES:
attnum = Anum_pg_statistic_ext_stxdependencies;
attnum = Anum_pg_statistic_ext_data_stxddependencies;
break;
case STATS_EXT_MCV:
attnum = Anum_pg_statistic_ext_stxmcv;
attnum = Anum_pg_statistic_ext_data_stxdmcv;
break;
default:
@ -312,70 +313,76 @@ lookup_var_attr_stats(Relation rel, Bitmapset *attrs,
/*
* statext_store
* Serializes the statistics and stores them into the pg_statistic_ext tuple.
* Serializes the statistics and stores them into the pg_statistic_ext_data
* tuple.
*/
static void
statext_store(Relation pg_stext, Oid statOid,
statext_store(Oid statOid,
MVNDistinct *ndistinct, MVDependencies *dependencies,
MCVList *mcv, VacAttrStats **stats)
{
HeapTuple stup,
oldtup;
Datum values[Natts_pg_statistic_ext];
bool nulls[Natts_pg_statistic_ext];
bool replaces[Natts_pg_statistic_ext];
Datum values[Natts_pg_statistic_ext_data];
bool nulls[Natts_pg_statistic_ext_data];
bool replaces[Natts_pg_statistic_ext_data];
Relation pg_stextdata;
memset(nulls, true, sizeof(nulls));
memset(replaces, false, sizeof(replaces));
memset(values, 0, sizeof(values));
/*
* Construct a new pg_statistic_ext tuple, replacing the calculated stats.
* Construct a new pg_statistic_ext_data tuple, replacing the calculated
* stats.
*/
if (ndistinct != NULL)
{
bytea *data = statext_ndistinct_serialize(ndistinct);
nulls[Anum_pg_statistic_ext_stxndistinct - 1] = (data == NULL);
values[Anum_pg_statistic_ext_stxndistinct - 1] = PointerGetDatum(data);
nulls[Anum_pg_statistic_ext_data_stxdndistinct - 1] = (data == NULL);
values[Anum_pg_statistic_ext_data_stxdndistinct - 1] = PointerGetDatum(data);
}
if (dependencies != NULL)
{
bytea *data = statext_dependencies_serialize(dependencies);
nulls[Anum_pg_statistic_ext_stxdependencies - 1] = (data == NULL);
values[Anum_pg_statistic_ext_stxdependencies - 1] = PointerGetDatum(data);
nulls[Anum_pg_statistic_ext_data_stxddependencies - 1] = (data == NULL);
values[Anum_pg_statistic_ext_data_stxddependencies - 1] = PointerGetDatum(data);
}
if (mcv != NULL)
{
bytea *data = statext_mcv_serialize(mcv, stats);
nulls[Anum_pg_statistic_ext_stxmcv - 1] = (data == NULL);
values[Anum_pg_statistic_ext_stxmcv - 1] = PointerGetDatum(data);
nulls[Anum_pg_statistic_ext_data_stxdmcv - 1] = (data == NULL);
values[Anum_pg_statistic_ext_data_stxdmcv - 1] = PointerGetDatum(data);
}
/* always replace the value (either by bytea or NULL) */
replaces[Anum_pg_statistic_ext_stxndistinct - 1] = true;
replaces[Anum_pg_statistic_ext_stxdependencies - 1] = true;
replaces[Anum_pg_statistic_ext_stxmcv - 1] = true;
replaces[Anum_pg_statistic_ext_data_stxdndistinct - 1] = true;
replaces[Anum_pg_statistic_ext_data_stxddependencies - 1] = true;
replaces[Anum_pg_statistic_ext_data_stxdmcv - 1] = true;
/* there should already be a pg_statistic_ext tuple */
oldtup = SearchSysCache1(STATEXTOID, ObjectIdGetDatum(statOid));
/* there should already be a pg_statistic_ext_data tuple */
oldtup = SearchSysCache1(STATEXTDATASTXOID, ObjectIdGetDatum(statOid));
if (!HeapTupleIsValid(oldtup))
elog(ERROR, "cache lookup failed for statistics object %u", statOid);
/* replace it */
pg_stextdata = table_open(StatisticExtDataRelationId, RowExclusiveLock);
stup = heap_modify_tuple(oldtup,
RelationGetDescr(pg_stext),
RelationGetDescr(pg_stextdata),
values,
nulls,
replaces);
ReleaseSysCache(oldtup);
CatalogTupleUpdate(pg_stext, &stup->t_self, stup);
CatalogTupleUpdate(pg_stextdata, &stup->t_self, stup);
heap_freetuple(stup);
table_close(pg_stextdata, RowExclusiveLock);
}
/* initialize multi-dimensional sort */

7
src/backend/statistics/mcv.c
View File

@ -19,6 +19,7 @@
#include "access/htup_details.h"
#include "catalog/pg_collation.h"
#include "catalog/pg_statistic_ext.h"
#include "catalog/pg_statistic_ext_data.h"
#include "fmgr.h"
#include "funcapi.h"
#include "nodes/nodeFuncs.h"
@ -429,13 +430,13 @@ statext_mcv_load(Oid mvoid)
MCVList *result;
bool isnull;
Datum mcvlist;
HeapTuple htup = SearchSysCache1(STATEXTOID, ObjectIdGetDatum(mvoid));
HeapTuple htup = SearchSysCache1(STATEXTDATASTXOID, ObjectIdGetDatum(mvoid));
if (!HeapTupleIsValid(htup))
elog(ERROR, "cache lookup failed for statistics object %u", mvoid);
mcvlist = SysCacheGetAttr(STATEXTOID, htup,
Anum_pg_statistic_ext_stxmcv, &isnull);
mcvlist = SysCacheGetAttr(STATEXTDATASTXOID, htup,
Anum_pg_statistic_ext_data_stxdmcv, &isnull);
if (isnull)
elog(ERROR,

7
src/backend/statistics/mvdistinct.c
View File

@ -27,6 +27,7 @@
#include "access/htup_details.h"
#include "catalog/pg_statistic_ext.h"
#include "catalog/pg_statistic_ext_data.h"
#include "utils/fmgrprotos.h"
#include "utils/lsyscache.h"
#include "lib/stringinfo.h"
@ -145,12 +146,12 @@ statext_ndistinct_load(Oid mvoid)
Datum ndist;
HeapTuple htup;
htup = SearchSysCache1(STATEXTOID, ObjectIdGetDatum(mvoid));
htup = SearchSysCache1(STATEXTDATASTXOID, ObjectIdGetDatum(mvoid));
if (!HeapTupleIsValid(htup))
elog(ERROR, "cache lookup failed for statistics object %u", mvoid);
ndist = SysCacheGetAttr(STATEXTOID, htup,
Anum_pg_statistic_ext_stxndistinct, &isnull);
ndist = SysCacheGetAttr(STATEXTDATASTXOID, htup,
Anum_pg_statistic_ext_data_stxdndistinct, &isnull);
if (isnull)
elog(ERROR,
"requested statistic kind \"%c\" is not yet built for statistics object %u",

12
src/backend/utils/cache/syscache.c vendored
View File

@ -62,6 +62,7 @@
#include "catalog/pg_replication_origin.h"
#include "catalog/pg_statistic.h"
#include "catalog/pg_statistic_ext.h"
#include "catalog/pg_statistic_ext_data.h"
#include "catalog/pg_subscription.h"
#include "catalog/pg_subscription_rel.h"
#include "catalog/pg_tablespace.h"
@ -727,6 +728,17 @@ static const struct cachedesc cacheinfo[] = {
},
32
},
{StatisticExtDataRelationId, /* STATEXTDATASTXOID */
StatisticExtDataStxoidIndexId,
1,
{
Anum_pg_statistic_ext_data_stxoid,
0,
0,
0
},
4
},
{StatisticExtRelationId, /* STATEXTNAMENSP */
StatisticExtNameIndexId,
2,

2
src/include/catalog/catversion.h
View File

@ -53,6 +53,6 @@
*/
/* yyyymmddN */
#define CATALOG_VERSION_NO 201906041
#define CATALOG_VERSION_NO 201906151
#endif

17
src/include/catalog/indexing.h
View File

@ -186,13 +186,6 @@ 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(stxname name_ops, stxnamespace oid_ops));
#define StatisticExtNameIndexId 3997
DECLARE_INDEX(pg_statistic_ext_relid_index, 3379, on pg_statistic_ext using btree(stxrelid 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));
@ -237,6 +230,16 @@ DECLARE_INDEX(pg_shdepend_reference_index, 1233, on pg_shdepend using btree(refc
DECLARE_UNIQUE_INDEX(pg_statistic_relid_att_inh_index, 2696, on pg_statistic using btree(starelid oid_ops, staattnum int2_ops, stainherit bool_ops));
#define StatisticRelidAttnumInhIndexId 2696
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(stxname name_ops, stxnamespace oid_ops));
#define StatisticExtNameIndexId 3997
DECLARE_INDEX(pg_statistic_ext_relid_index, 3379, on pg_statistic_ext using btree(stxrelid oid_ops));
#define StatisticExtRelidIndexId 3379
DECLARE_UNIQUE_INDEX(pg_statistic_ext_data_stxoid_index, 3433, on pg_statistic_ext_data using btree(stxoid oid_ops));
#define StatisticExtDataStxoidIndexId 3433
DECLARE_UNIQUE_INDEX(pg_tablespace_oid_index, 2697, on pg_tablespace using btree(oid oid_ops));
#define TablespaceOidIndexId 2697
DECLARE_UNIQUE_INDEX(pg_tablespace_spcname_index, 2698, on pg_tablespace using btree(spcname name_ops));

9
src/include/catalog/pg_statistic_ext.h
View File

@ -1,8 +1,12 @@
/*-------------------------------------------------------------------------
*
* pg_statistic_ext.h
* definition of the "extended statistics" system catalog (pg_statistic_ext)
* definition of the "extended statistics" system catalog
* (pg_statistic_ext)
*
* Note that pg_statistic_ext contains the definitions of extended statistics
* objects, created by CREATE STATISTICS, but not the actual statistical data,
* created by running ANALYZE.
*
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
@ -47,9 +51,6 @@ CATALOG(pg_statistic_ext,3381,StatisticExtRelationId)
#ifdef CATALOG_VARLEN
char stxkind[1] BKI_FORCE_NOT_NULL; /* statistics kinds requested
* to build */
pg_ndistinct stxndistinct; /* ndistinct coefficients (serialized) */
pg_dependencies stxdependencies; /* dependencies (serialized) */
pg_mcv_list stxmcv; /* MCV (serialized) */
#endif
} FormData_pg_statistic_ext;

52
src/include/catalog/pg_statistic_ext_data.h Normal file
View File

@ -0,0 +1,52 @@
/*-------------------------------------------------------------------------
*
* pg_statistic_ext_data.h
* definition of the "extended statistics data" system catalog
* (pg_statistic_ext_data)
*
* This catalog stores the statistical data for extended statistics objects.
*
* Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/catalog/pg_statistic_ext_data.h
*
* NOTES
* The Catalog.pm module reads this file and derives schema
* information.
*
*-------------------------------------------------------------------------
*/
#ifndef PG_STATISTIC_EXT_DATA_H
#define PG_STATISTIC_EXT_DATA_H
#include "catalog/genbki.h"
#include "catalog/pg_statistic_ext_data_d.h"
/* ----------------
* pg_statistic_ext_data definition. cpp turns this into
* typedef struct FormData_pg_statistic_ext_data
* ----------------
*/
CATALOG(pg_statistic_ext_data,3429,StatisticExtDataRelationId)
{
Oid stxoid; /* statistics object this data is for */
#ifdef CATALOG_VARLEN /* variable-length fields start here */
pg_ndistinct stxdndistinct; /* ndistinct coefficients (serialized) */
pg_dependencies stxddependencies; /* dependencies (serialized) */
pg_mcv_list stxdmcv; /* MCV (serialized) */
#endif
} FormData_pg_statistic_ext_data;
/* ----------------
* Form_pg_statistic_ext_data corresponds to a pointer to a tuple with
* the format of pg_statistic_ext_data relation.
* ----------------
*/
typedef FormData_pg_statistic_ext_data *Form_pg_statistic_ext_data;
#endif /* PG_STATISTIC_EXT_DATA_H */

1
src/include/catalog/toasting.h
View File

@ -70,6 +70,7 @@ 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_statistic_ext_data, 3430, 3431);
DECLARE_TOAST(pg_trigger, 2336, 2337);
DECLARE_TOAST(pg_ts_dict, 4169, 4170);
DECLARE_TOAST(pg_type, 4171, 4172);

1
src/include/utils/syscache.h
View File

@ -86,6 +86,7 @@ enum SysCacheIdentifier
REPLORIGNAME,
RULERELNAME,
SEQRELID,
STATEXTDATASTXOID,
STATEXTNAMENSP,
STATEXTOID,
STATRELATTINH,

8
src/test/regress/expected/oidjoins.out
View File

@ -985,6 +985,14 @@ WHERE stxowner != 0 AND
------+----------
(0 rows)
SELECT ctid, stxoid
FROM pg_catalog.pg_statistic_ext_data fk
WHERE stxoid != 0 AND
NOT EXISTS(SELECT 1 FROM pg_catalog.pg_statistic_ext pk WHERE pk.oid = fk.stxoid);
ctid | stxoid
------+--------
(0 rows)
SELECT ctid, spcowner
FROM pg_catalog.pg_tablespace fk
WHERE spcowner != 0 AND

1
src/test/regress/expected/sanity_check.out
View File

@ -149,6 +149,7 @@ pg_shdescription|t
pg_shseclabel|t
pg_statistic|t
pg_statistic_ext|t
pg_statistic_ext_data|t
pg_subscription|t
pg_subscription_rel|t
pg_tablespace|t

38
src/test/regress/expected/stats_ext.out
View File

@ -199,9 +199,11 @@ SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY b, c
-- correct command
CREATE STATISTICS s10 ON a, b, c FROM ndistinct;
ANALYZE ndistinct;
SELECT stxkind, stxndistinct
FROM pg_statistic_ext WHERE stxrelid = 'ndistinct'::regclass;
stxkind | stxndistinct
SELECT s.stxkind, d.stxdndistinct
FROM pg_statistic_ext s, pg_statistic_ext_data d
WHERE s.stxrelid = 'ndistinct'::regclass
AND d.stxoid = s.oid;
stxkind | stxdndistinct
---------+-----------------------------------------------------
{d,f,m} | {"3, 4": 11, "3, 6": 11, "4, 6": 11, "3, 4, 6": 11}
(1 row)
@ -246,9 +248,11 @@ INSERT INTO ndistinct (a, b, c, filler1)
cash_words(mod(i,33)::int::money)
FROM generate_series(1,5000) s(i);
ANALYZE ndistinct;
SELECT stxkind, stxndistinct
FROM pg_statistic_ext WHERE stxrelid = 'ndistinct'::regclass;
stxkind | stxndistinct
SELECT s.stxkind, d.stxdndistinct
FROM pg_statistic_ext s, pg_statistic_ext_data d
WHERE s.stxrelid = 'ndistinct'::regclass
AND d.stxoid = s.oid;
stxkind | stxdndistinct
---------+------------------------------------------------------------
{d,f,m} | {"3, 4": 2550, "3, 6": 800, "4, 6": 1632, "3, 4, 6": 5000}
(1 row)
@ -285,10 +289,12 @@ SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, d
(1 row)
DROP STATISTICS s10;
SELECT stxkind, stxndistinct
FROM pg_statistic_ext WHERE stxrelid = 'ndistinct'::regclass;
stxkind | stxndistinct
---------+--------------
SELECT s.stxkind, d.stxdndistinct
FROM pg_statistic_ext s, pg_statistic_ext_data d
WHERE s.stxrelid = 'ndistinct'::regclass
AND d.stxoid = s.oid;
stxkind | stxdndistinct
---------+---------------
(0 rows)
-- dropping the statistics results in under-estimates
@ -537,7 +543,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a <= 4 AND b <
-- check change of unrelated column type does not reset the MCV statistics
ALTER TABLE mcv_lists ALTER COLUMN d TYPE VARCHAR(64);
SELECT stxmcv IS NOT NULL FROM pg_statistic_ext WHERE stxname = 'mcv_lists_stats';
SELECT d.stxdmcv IS NOT NULL
FROM pg_statistic_ext s, pg_statistic_ext_data d
WHERE s.stxname = 'mcv_lists_stats'
AND d.stxoid = s.oid;
?column?
----------
t
@ -600,8 +609,11 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a IS NULL AND
TRUNCATE mcv_lists;
INSERT INTO mcv_lists (a, b, c) SELECT 1, 2, 3 FROM generate_series(1,1000) s(i);
ANALYZE mcv_lists;
SELECT m.* FROM pg_statistic_ext,
pg_mcv_list_items(stxmcv) m WHERE stxname = 'mcv_lists_stats';
SELECT m.*
FROM pg_statistic_ext s, pg_statistic_ext_data d,
pg_mcv_list_items(d.stxdmcv) m
WHERE s.stxname = 'mcv_lists_stats'
AND d.stxoid = s.oid;
index | values | nulls | frequency | base_frequency
-------+-----------+---------+-----------+----------------
0 | {1, 2, 3} | {f,f,f} | 1 | 1

4
src/test/regress/sql/oidjoins.sql
View File

@ -493,6 +493,10 @@ SELECT ctid, stxowner
FROM pg_catalog.pg_statistic_ext fk
WHERE stxowner != 0 AND
NOT EXISTS(SELECT 1 FROM pg_catalog.pg_authid pk WHERE pk.oid = fk.stxowner);
SELECT ctid, stxoid
FROM pg_catalog.pg_statistic_ext_data fk
WHERE stxoid != 0 AND
NOT EXISTS(SELECT 1 FROM pg_catalog.pg_statistic_ext pk WHERE pk.oid = fk.stxoid);
SELECT ctid, spcowner
FROM pg_catalog.pg_tablespace fk
WHERE spcowner != 0 AND

30
src/test/regress/sql/stats_ext.sql
View File

@ -144,8 +144,10 @@ CREATE STATISTICS s10 ON a, b, c FROM ndistinct;
ANALYZE ndistinct;
SELECT stxkind, stxndistinct
FROM pg_statistic_ext WHERE stxrelid = 'ndistinct'::regclass;
SELECT s.stxkind, d.stxdndistinct
FROM pg_statistic_ext s, pg_statistic_ext_data d
WHERE s.stxrelid = 'ndistinct'::regclass
AND d.stxoid = s.oid;
-- Hash Aggregate, thanks to estimates improved by the statistic
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
@ -170,8 +172,10 @@ INSERT INTO ndistinct (a, b, c, filler1)
ANALYZE ndistinct;
SELECT stxkind, stxndistinct
FROM pg_statistic_ext WHERE stxrelid = 'ndistinct'::regclass;
SELECT s.stxkind, d.stxdndistinct
FROM pg_statistic_ext s, pg_statistic_ext_data d
WHERE s.stxrelid = 'ndistinct'::regclass
AND d.stxoid = s.oid;
-- correct esimates
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
@ -186,8 +190,10 @@ SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, d
DROP STATISTICS s10;
SELECT stxkind, stxndistinct
FROM pg_statistic_ext WHERE stxrelid = 'ndistinct'::regclass;
SELECT s.stxkind, d.stxdndistinct
FROM pg_statistic_ext s, pg_statistic_ext_data d
WHERE s.stxrelid = 'ndistinct'::regclass
AND d.stxoid = s.oid;
-- dropping the statistics results in under-estimates
SELECT * FROM check_estimated_rows('SELECT COUNT(*) FROM ndistinct GROUP BY a, b');
@ -335,7 +341,10 @@ SELECT * FROM check_estimated_rows('SELECT * FROM mcv_lists WHERE a <= 4 AND b <
-- check change of unrelated column type does not reset the MCV statistics
ALTER TABLE mcv_lists ALTER COLUMN d TYPE VARCHAR(64);
SELECT stxmcv IS NOT NULL FROM pg_statistic_ext WHERE stxname = 'mcv_lists_stats';
SELECT d.stxdmcv IS NOT NULL
FROM pg_statistic_ext s, pg_statistic_ext_data d
WHERE s.stxname = 'mcv_lists_stats'
AND d.stxoid = s.oid;
-- check change of column type resets the MCV statistics
ALTER TABLE mcv_lists ALTER COLUMN c TYPE numeric;
@ -378,8 +387,11 @@ TRUNCATE mcv_lists;
INSERT INTO mcv_lists (a, b, c) SELECT 1, 2, 3 FROM generate_series(1,1000) s(i);
ANALYZE mcv_lists;
SELECT m.* FROM pg_statistic_ext,
pg_mcv_list_items(stxmcv) m WHERE stxname = 'mcv_lists_stats';
SELECT m.*
FROM pg_statistic_ext s, pg_statistic_ext_data d,
pg_mcv_list_items(d.stxdmcv) m
WHERE s.stxname = 'mcv_lists_stats'
AND d.stxoid = s.oid;
-- mcv with arrays
CREATE TABLE mcv_lists_arrays (

2
src/tools/pgindent/typedefs.list
View File

@ -729,6 +729,7 @@ FormData_pg_sequence_data
FormData_pg_shdepend
FormData_pg_statistic
FormData_pg_statistic_ext
FormData_pg_statistic_ext_data
FormData_pg_subscription
FormData_pg_subscription_rel
FormData_pg_tablespace
@ -786,6 +787,7 @@ Form_pg_sequence_data
Form_pg_shdepend
Form_pg_statistic
Form_pg_statistic_ext
Form_pg_statistic_ext_data
Form_pg_subscription
Form_pg_subscription_rel
Form_pg_tablespace