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enable_constraint_exclusion => constraint_exclusion
Also improve wording.
1 parent 8ad3965 commit a7f4925

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-33
lines changed

8 files changed

+31
-33
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‎doc/TODO

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -385,7 +385,7 @@ SQL Commands
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* Add GUC to issue notice about queries that use unjoined tables
387387
* Allow EXPLAIN to identify tables that were skipped because of
388-
enable_constraint_exclusion
388+
constraint_exclusion
389389
* Allow EXPLAIN output to be more easily processed by scripts
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391391

@@ -769,7 +769,7 @@ Indexes
769769
* Allow the creation of indexes with mixed ascending/descending specifiers
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* -Fix incorrect rtree results due to wrong assumptions about "over"
771771
operator semantics
772-
* Allow enable_constraint_exclusion to work for UNIONs like it does for
772+
* Allow constraint_exclusion to work for UNIONs like it does for
773773
inheritance, and allow it to work for UPDATE and DELETE queries
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775775

‎doc/src/FAQ/TODO.html

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -355,7 +355,7 @@ <h1><a name="section_8">SQL Commands</a></h1>
355355
</p>
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</li><li>Add GUC to issue notice about queries that use unjoined tables
357357
</li><li>Allow EXPLAIN to identify tables that were skipped because of
358-
enable_constraint_exclusion
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constraint_exclusion
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</li><li>Allow EXPLAIN output to be more easily processed by scripts
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</li><li>CREATE
361361
<ul>
@@ -694,7 +694,7 @@ <h1><a name="section_13">Indexes</a></h1>
694694
</li><li>Allow the creation of indexes with mixed ascending/descending specifiers
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</li><li>-<em>Fix incorrect rtree results due to wrong assumptions about "over"</em>
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operator semantics
697-
</li><li>Allow enable_constraint_exclusion to work for UNIONs like it does for
697+
</li><li>Allow constraint_exclusion to work for UNIONs like it does for
698698
inheritance, and allow it to work for UPDATE and DELETE queries
699699
</li><li>GIST
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<ul>

‎doc/src/sgml/runtime.sgml

Lines changed: 13 additions & 13 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
<!--
2-
$PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.346 2005/08/21 03:39:26 tgl Exp $
2+
$PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.347 2005/08/22 17:34:56 momjian Exp $
33
-->
44

55
<chapter Id="runtime">
@@ -2352,24 +2352,24 @@ archive_command = 'copy "%p" /mnt/server/archivedir/"%f"' # Windows
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</listitem>
23532353
</varlistentry>
23542354

2355-
<varlistentry id="guc-enable-constraint-exclusion" xreflabel="enable_constraint_exclusion">
2356-
<term><varname>enable_constraint_exclusion</varname> (<type>boolean</type>)</term>
2355+
<varlistentry id="guc-constraint-exclusion" xreflabel="constraint_exclusion">
2356+
<term><varname>constraint_exclusion</varname> (<type>boolean</type>)</term>
23572357
<indexterm>
23582358
<primary>constraint exclusion</primary>
23592359
</indexterm>
23602360
<indexterm>
2361-
<primary><varname>enable_constraint_exclusion</> configuration parameter</primary>
2361+
<primary><varname>constraint_exclusion</> configuration parameter</primary>
23622362
</indexterm>
23632363
<listitem>
23642364
<para>
2365-
Enables or disables the query planner's use of table constraints.
2366-
The default is <literal>off</>.
2365+
Enables or disables the query planner's use of table constraints to
2366+
limit table access. The default is <literal>off</>.
23672367
</para>
23682368

23692369
<para>
23702370
When this parameter is <literal>on</>, the planner compares query
2371-
conditions to table CHECK constraints, and omits scanning tables
2372-
for which the conditions contradict the constraints. (Presently
2371+
conditions with table CHECK constraints, and omits scanning tables
2372+
where the conditions contradict the constraints. (Presently
23732373
this is done only for child tables of inheritance scans.) For
23742374
example:
23752375

@@ -2387,15 +2387,15 @@ SELECT * FROM parent WHERE key = 2400;
23872387
</para>
23882388

23892389
<para>
2390-
Currently, <varname>enable_constraint_exclusion</> defaults to
2391-
<literal>off</>, because it creates a risk of wrong answers when
2392-
query plans are cached: if a table constraint is changed or dropped,
2393-
the previously generated plan may now be wrong, and there is no
2390+
Currently, <varname>constraint_exclusion</> defaults to
2391+
<literal>off</>, because it risks incorrect results if
2392+
query plans are cached --- if a table constraint is changed or dropped,
2393+
the previously generated plan might now be wrong, and there is no
23942394
built-in mechanism to force re-planning. (This deficiency will
23952395
probably be addressed in a future
23962396
<productname>PostgreSQL</productname> release.) Another reason
23972397
for keeping it off is that the constraint checks are relatively
2398-
expensive to make, and in many circumstances will yield no savings.
2398+
expensive, and in many circumstances will yield no savings.
23992399
It is recommended to turn this on only if you are actually using
24002400
partitioned tables designed to take advantage of the feature.
24012401
</para>

‎src/backend/optimizer/path/allpaths.c

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.135 2005/07/23 21:05:46 tgl Exp $
11+
* $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.136 2005/08/22 17:34:58 momjian Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -36,7 +36,7 @@
3636

3737

3838
/* These parameters are set by GUC */
39-
bool enable_constraint_exclusion = false;
39+
bool constraint_exclusion = false;
4040
bool enable_geqo = false; /* just in case GUC doesn't set it */
4141
int geqo_threshold;
4242

@@ -318,7 +318,7 @@ set_inherited_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
318318
* exclusion, just ignore it. (We have to have converted the
319319
* baserestrictinfo Vars before we can make the test.)
320320
*/
321-
if (enable_constraint_exclusion)
321+
if (constraint_exclusion)
322322
{
323323
List *constraint_pred;
324324

‎src/backend/utils/misc/guc.c

Lines changed: 6 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,7 @@
1010
* Written by Peter Eisentraut <peter_e@gmx.net>.
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*
1212
* IDENTIFICATION
13-
* $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.285 2005/08/21 03:39:34 tgl Exp $
13+
* $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.286 2005/08/22 17:34:59 momjian Exp $
1414
*
1515
*--------------------------------------------------------------------
1616
*/
@@ -453,13 +453,12 @@ static struct config_bool ConfigureNamesBool[] =
453453
true, NULL, NULL
454454
},
455455
{
456-
{"enable_constraint_exclusion", PGC_USERSET, QUERY_TUNING_OTHER,
457-
gettext_noop("Enables the planner's use of constraints in queries."),
458-
gettext_noop("Constraints will be examined to exclude tables "
459-
"that can be proven not to be required to produce "
460-
"a correct result for the query.")
456+
{"constraint_exclusion", PGC_USERSET, QUERY_TUNING_OTHER,
457+
gettext_noop("Enables the planner to use constraints to limit table access."),
458+
gettext_noop("This prevents table access if the table constraints "
459+
"guarantee that table access is necessary.")
461460
},
462-
&enable_constraint_exclusion,
461+
&constraint_exclusion,
463462
false, NULL, NULL
464463
},
465464
{

‎src/backend/utils/misc/postgresql.conf.sample

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -190,7 +190,7 @@
190190
# - Other Planner Options -
191191

192192
#default_statistics_target = 10 # range 1-1000
193-
#enable_constraint_exclusion = off
193+
#constraint_exclusion = off
194194
#from_collapse_limit = 8
195195
#join_collapse_limit = 8 # 1 disables collapsing of explicit
196196
# JOINs

‎src/include/optimizer/cost.h

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
88
* Portions Copyright (c) 1994, Regents of the University of California
99
*
10-
* $PostgreSQL: pgsql/src/include/optimizer/cost.h,v 1.69 2005/07/23 21:05:48 tgl Exp $
10+
* $PostgreSQL: pgsql/src/include/optimizer/cost.h,v 1.70 2005/08/22 17:35:03 momjian Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -49,7 +49,7 @@ extern bool enable_hashagg;
4949
extern bool enable_nestloop;
5050
extern bool enable_mergejoin;
5151
extern bool enable_hashjoin;
52-
extern bool enable_constraint_exclusion;
52+
extern bool constraint_exclusion;
5353

5454
extern double clamp_row_est(double nrows);
5555
extern void cost_seqscan(Path *path, PlannerInfo *root, RelOptInfo *baserel);

‎src/test/regress/expected/rangefuncs.out

Lines changed: 2 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -1,8 +1,7 @@
11
SELECT name, setting FROM pg_settings WHERE name LIKE 'enable%';
22
name | setting
3-
-----------------------------+---------
3+
-------------------+---------
44
enable_bitmapscan | on
5-
enable_constraint_exclusion | off
65
enable_hashagg | on
76
enable_hashjoin | on
87
enable_indexscan | on
@@ -11,7 +10,7 @@ SELECT name, setting FROM pg_settings WHERE name LIKE 'enable%';
1110
enable_seqscan | on
1211
enable_sort | on
1312
enable_tidscan | on
14-
(10 rows)
13+
(9 rows)
1514

1615
CREATE TABLE foo2(fooid int, f2 int);
1716
INSERT INTO foo2 VALUES(1, 11);

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