Location via proxy:   [ UP ]  
[Report a bug]   [Manage cookies]                
Skip to content

Commit e839c8e

Browse files
jeff-davisjeff-davis
committed
Create functions pg_set_relation_stats, pg_clear_relation_stats.
These functions are used to tweak statistics on any relation, provided that the user has MAINTAIN privilege on the relation, or is the database owner. Bump catalog version. Author: Corey Huinker Discussion: https://postgr.es/m/CADkLM=eErgzn7ECDpwFcptJKOk9SxZEk5Pot4d94eVTZsvj3gw@mail.gmail.com
1 parent 6f782a2 commit e839c8e

File tree

12 files changed

+700
-3
lines changed

12 files changed

+700
-3
lines changed

‎doc/src/sgml/func.sgml

Lines changed: 94 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -30135,6 +30135,100 @@ DETAIL: Make sure pg_wal_replay_wait() isn't called within a transaction with a
3013530135
</tgroup>
3013630136
</table>
3013730137

30138+
<para>
30139+
<xref linkend="functions-admin-statsmod"/> lists functions used to
30140+
manipulate statistics.
30141+
<warning>
30142+
<para>
30143+
Changes made by these statistics manipulation functions are likely to be
30144+
overwritten by <link linkend="autovacuum">autovacuum</link> (or manual
30145+
<command>VACUUM</command> or <command>ANALYZE</command>) and should be
30146+
considered temporary.
30147+
</para>
30148+
</warning>
30149+
</para>
30150+
30151+
<table id="functions-admin-statsmod">
30152+
<title>Database Object Statistics Manipulation Functions</title>
30153+
<tgroup cols="1">
30154+
<thead>
30155+
<row>
30156+
<entry role="func_table_entry"><para role="func_signature">
30157+
Function
30158+
</para>
30159+
<para>
30160+
Description
30161+
</para></entry>
30162+
</row>
30163+
</thead>
30164+
30165+
<tbody>
30166+
<row>
30167+
<entry role="func_table_entry">
30168+
<para role="func_signature">
30169+
<indexterm>
30170+
<primary>pg_set_relation_stats</primary>
30171+
</indexterm>
30172+
<function>pg_set_relation_stats</function> (
30173+
<parameter>relation</parameter> <type>regclass</type>
30174+
<optional>, <parameter>relpages</parameter> <type>integer</type></optional>
30175+
<optional>, <parameter>reltuples</parameter> <type>real</type></optional>
30176+
<optional>, <parameter>relallvisible</parameter> <type>integer</type></optional> )
30177+
<returnvalue>boolean</returnvalue>
30178+
</para>
30179+
<para>
30180+
Updates relation-level statistics for the given relation to the
30181+
specified values. The parameters correspond to columns in <link
30182+
linkend="catalog-pg-class"><structname>pg_class</structname></link>. Unspecified
30183+
or <literal>NULL</literal> values leave the setting
30184+
unchanged. Returns <literal>true</literal> if a change was made;
30185+
<literal>false</literal> otherwise.
30186+
</para>
30187+
<para>
30188+
Ordinarily, these statistics are collected automatically or updated
30189+
as a part of <xref linkend="sql-vacuum"/> or <xref
30190+
linkend="sql-analyze"/>, so it's not necessary to call this
30191+
function. However, it may be useful when testing the effects of
30192+
statistics on the planner to understand or anticipate plan changes.
30193+
</para>
30194+
<para>
30195+
The caller must have the <literal>MAINTAIN</literal> privilege on
30196+
the table or be the owner of the database.
30197+
</para>
30198+
<para>
30199+
The value of <structfield>relpages</structfield> must be greater than
30200+
or equal to <literal>0</literal>,
30201+
<structfield>reltuples</structfield> must be greater than or equal to
30202+
<literal>-1.0</literal>, and <structfield>relallvisible</structfield>
30203+
must be greater than or equal to <literal>0</literal>.
30204+
</para>
30205+
</entry>
30206+
</row>
30207+
30208+
<row>
30209+
<entry role="func_table_entry">
30210+
<para role="func_signature">
30211+
<indexterm>
30212+
<primary>pg_clear_relation_stats</primary>
30213+
</indexterm>
30214+
<function>pg_clear_relation_stats</function> ( <parameter>relation</parameter> <type>regclass</type> )
30215+
<returnvalue>boolean</returnvalue>
30216+
</para>
30217+
<para>
30218+
Clears table-level statistics for the given relation, as though the
30219+
table was newly created. Returns <literal>true</literal> if a change
30220+
was made; <literal>false</literal> otherwise.
30221+
</para>
30222+
<para>
30223+
The caller must have the <literal>MAINTAIN</literal> privilege on
30224+
the table or be the owner of the database.
30225+
</para>
30226+
</entry>
30227+
</row>
30228+
</tbody>
30229+
</tgroup>
30230+
</table>
30231+
3013830232
<para>
3013930233
<xref linkend="functions-info-partition"/> lists functions that provide
3014030234
information about the structure of partitioned tables.

‎src/backend/catalog/system_functions.sql

Lines changed: 10 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -639,6 +639,16 @@ LANGUAGE INTERNAL
639639
CALLED ON NULL INPUT VOLATILE PARALLEL SAFE
640640
AS 'pg_stat_reset_slru';
641641

642+
CREATE OR REPLACE FUNCTION
643+
pg_set_relation_stats(relation regclass,
644+
relpages integer DEFAULT NULL,
645+
reltuples real DEFAULT NULL,
646+
relallvisible integer DEFAULT NULL)
647+
RETURNS bool
648+
LANGUAGE INTERNAL
649+
CALLED ON NULL INPUT VOLATILE
650+
AS 'pg_set_relation_stats';
651+
642652
--
643653
-- The default permissions for functions mean that anyone can execute them.
644654
-- A number of functions shouldn't be executable by just anyone, but rather

‎src/backend/statistics/Makefile

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -16,6 +16,8 @@ OBJS = \
1616
dependencies.o \
1717
extended_stats.o \
1818
mcv.o \
19-
mvdistinct.o
19+
mvdistinct.o \
20+
relation_stats.o \
21+
stat_utils.o
2022

2123
include $(top_srcdir)/src/backend/common.mk

‎src/backend/statistics/meson.build

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -5,4 +5,6 @@ backend_sources += files(
55
'extended_stats.c',
66
'mcv.c',
77
'mvdistinct.c',
8+
'relation_stats.c',
9+
'stat_utils.c'
810
)

‎src/backend/statistics/relation_stats.c

Lines changed: 210 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,210 @@
1+
/*-------------------------------------------------------------------------
2+
* relation_stats.c
3+
*
4+
* PostgreSQL relation statistics manipulation
5+
*
6+
* Code supporting the direct import of relation statistics, similar to
7+
* what is done by the ANALYZE command.
8+
*
9+
* Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
10+
* Portions Copyright (c) 1994, Regents of the University of California
11+
*
12+
* IDENTIFICATION
13+
* src/backend/statistics/relation_stats.c
14+
*
15+
*-------------------------------------------------------------------------
16+
*/
17+
18+
#include "postgres.h"
19+
20+
#include "access/heapam.h"
21+
#include "catalog/indexing.h"
22+
#include "statistics/stat_utils.h"
23+
#include "utils/fmgrprotos.h"
24+
#include "utils/syscache.h"
25+
26+
#define DEFAULT_RELPAGES Int32GetDatum(0)
27+
#define DEFAULT_RELTUPLES Float4GetDatum(-1.0)
28+
#define DEFAULT_RELALLVISIBLE Int32GetDatum(0)
29+
30+
/*
31+
* Positional argument numbers, names, and types for
32+
* relation_statistics_update().
33+
*/
34+
35+
enum relation_stats_argnum
36+
{
37+
RELATION_ARG = 0,
38+
RELPAGES_ARG,
39+
RELTUPLES_ARG,
40+
RELALLVISIBLE_ARG,
41+
NUM_RELATION_STATS_ARGS
42+
};
43+
44+
static struct StatsArgInfo relarginfo[] =
45+
{
46+
[RELATION_ARG] = {"relation", REGCLASSOID},
47+
[RELPAGES_ARG] = {"relpages", INT4OID},
48+
[RELTUPLES_ARG] = {"reltuples", FLOAT4OID},
49+
[RELALLVISIBLE_ARG] = {"relallvisible", INT4OID},
50+
[NUM_RELATION_STATS_ARGS] = {0}
51+
};
52+
53+
static bool relation_statistics_update(FunctionCallInfo fcinfo, int elevel);
54+
55+
/*
56+
* Internal function for modifying statistics for a relation.
57+
*/
58+
static bool
59+
relation_statistics_update(FunctionCallInfo fcinfo, int elevel)
60+
{
61+
Oid reloid;
62+
Relation crel;
63+
HeapTuple ctup;
64+
Form_pg_class pgcform;
65+
int replaces[3] = {0};
66+
Datum values[3] = {0};
67+
bool nulls[3] = {0};
68+
int ncols = 0;
69+
TupleDesc tupdesc;
70+
HeapTuple newtup;
71+
72+
73+
stats_check_required_arg(fcinfo, relarginfo, RELATION_ARG);
74+
reloid = PG_GETARG_OID(RELATION_ARG);
75+
76+
stats_lock_check_privileges(reloid);
77+
78+
/*
79+
* Take RowExclusiveLock on pg_class, consistent with
80+
* vac_update_relstats().
81+
*/
82+
crel = table_open(RelationRelationId, RowExclusiveLock);
83+
84+
tupdesc = RelationGetDescr(crel);
85+
ctup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(reloid));
86+
if (!HeapTupleIsValid(ctup))
87+
{
88+
ereport(elevel,
89+
(errcode(ERRCODE_OBJECT_IN_USE),
90+
errmsg("pg_class entry for relid %u not found", reloid)));
91+
table_close(crel, RowExclusiveLock);
92+
return false;
93+
}
94+
95+
pgcform = (Form_pg_class) GETSTRUCT(ctup);
96+
97+
/* relpages */
98+
if (!PG_ARGISNULL(RELPAGES_ARG))
99+
{
100+
int32 relpages = PG_GETARG_INT32(RELPAGES_ARG);
101+
102+
if (relpages < -1)
103+
{
104+
ereport(elevel,
105+
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
106+
errmsg("relpages cannot be < -1")));
107+
table_close(crel, RowExclusiveLock);
108+
return false;
109+
}
110+
111+
if (relpages != pgcform->relpages)
112+
{
113+
replaces[ncols] = Anum_pg_class_relpages;
114+
values[ncols] = Int32GetDatum(relpages);
115+
ncols++;
116+
}
117+
}
118+
119+
if (!PG_ARGISNULL(RELTUPLES_ARG))
120+
{
121+
float reltuples = PG_GETARG_FLOAT4(RELTUPLES_ARG);
122+
123+
if (reltuples < -1.0)
124+
{
125+
ereport(elevel,
126+
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
127+
errmsg("reltuples cannot be < -1.0")));
128+
table_close(crel, RowExclusiveLock);
129+
return false;
130+
}
131+
132+
if (reltuples != pgcform->reltuples)
133+
{
134+
replaces[ncols] = Anum_pg_class_reltuples;
135+
values[ncols] = Float4GetDatum(reltuples);
136+
ncols++;
137+
}
138+
}
139+
140+
if (!PG_ARGISNULL(RELALLVISIBLE_ARG))
141+
{
142+
int32 relallvisible = PG_GETARG_INT32(RELALLVISIBLE_ARG);
143+
144+
if (relallvisible < 0)
145+
{
146+
ereport(elevel,
147+
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
148+
errmsg("relallvisible cannot be < 0")));
149+
table_close(crel, RowExclusiveLock);
150+
return false;
151+
}
152+
153+
if (relallvisible != pgcform->relallvisible)
154+
{
155+
replaces[ncols] = Anum_pg_class_relallvisible;
156+
values[ncols] = Int32GetDatum(relallvisible);
157+
ncols++;
158+
}
159+
}
160+
161+
/* only update pg_class if there is a meaningful change */
162+
if (ncols == 0)
163+
{
164+
table_close(crel, RowExclusiveLock);
165+
return false;
166+
}
167+
168+
newtup = heap_modify_tuple_by_cols(ctup, tupdesc, ncols, replaces, values,
169+
nulls);
170+
171+
CatalogTupleUpdate(crel, &newtup->t_self, newtup);
172+
heap_freetuple(newtup);
173+
174+
/* release the lock, consistent with vac_update_relstats() */
175+
table_close(crel, RowExclusiveLock);
176+
177+
return true;
178+
}
179+
180+
/*
181+
* Set statistics for a given pg_class entry.
182+
*/
183+
Datum
184+
pg_set_relation_stats(PG_FUNCTION_ARGS)
185+
{
186+
PG_RETURN_BOOL(relation_statistics_update(fcinfo, ERROR));
187+
}
188+
189+
/*
190+
* Clear statistics for a given pg_class entry; that is, set back to initial
191+
* stats for a newly-created table.
192+
*/
193+
Datum
194+
pg_clear_relation_stats(PG_FUNCTION_ARGS)
195+
{
196+
LOCAL_FCINFO(newfcinfo, 4);
197+
198+
InitFunctionCallInfoData(*newfcinfo, NULL, 4, InvalidOid, NULL, NULL);
199+
200+
newfcinfo->args[0].value = PG_GETARG_OID(0);
201+
newfcinfo->args[0].isnull = PG_ARGISNULL(0);
202+
newfcinfo->args[1].value = DEFAULT_RELPAGES;
203+
newfcinfo->args[1].isnull = false;
204+
newfcinfo->args[2].value = DEFAULT_RELTUPLES;
205+
newfcinfo->args[2].isnull = false;
206+
newfcinfo->args[3].value = DEFAULT_RELALLVISIBLE;
207+
newfcinfo->args[3].isnull = false;
208+
209+
PG_RETURN_BOOL(relation_statistics_update(newfcinfo, ERROR));
210+
}

0 commit comments

Comments
 (0)