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Tweak default memory context allocation policy so that a context is not
given any malloc block until something is first allocated in it; but thereafter, MemoryContextReset won't release that first malloc block. This preserves the quick-reset property of the original policy, without forcing 8K to be allocated to every context whether any of it is ever used or not. Also, remove some more no-longer-needed explicit freeing during ExecEndPlan.
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11 files changed

+66
-99
lines changed

11 files changed

+66
-99
lines changed

‎src/backend/commands/prepare.c

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -6,7 +6,7 @@
66
* Copyright (c) 2002, PostgreSQL Global Development Group
77
*
88
* IDENTIFICATION
9-
* $Header: /cvsroot/pgsql/src/backend/commands/prepare.c,v 1.11 2002/12/15 16:17:42 tgl Exp $
9+
* $Header: /cvsroot/pgsql/src/backend/commands/prepare.c,v 1.12 2002/12/15 21:01:34 tgl Exp $
1010
*
1111
*-------------------------------------------------------------------------
1212
*/
@@ -256,9 +256,9 @@ StoreQuery(const char *stmt_name, List *query_list, List *plan_list,
256256
/* Make a permanent memory context for the hashtable entry */
257257
entrycxt = AllocSetContextCreate(TopMemoryContext,
258258
stmt_name,
259-
1024,
260-
1024,
261-
ALLOCSET_DEFAULT_MAXSIZE);
259+
ALLOCSET_SMALL_MINSIZE,
260+
ALLOCSET_SMALL_INITSIZE,
261+
ALLOCSET_SMALL_MAXSIZE);
262262

263263
oldcxt = MemoryContextSwitchTo(entrycxt);
264264

‎src/backend/commands/trigger.c

Lines changed: 4 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
* Portions Copyright (c) 1994, Regents of the University of California
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/commands/trigger.c,v 1.141 2002/11/25 03:36:50 tgl Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/commands/trigger.c,v 1.142 2002/12/15 21:01:34 tgl Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -2008,13 +2008,9 @@ deferredTriggerInvokeEvents(bool immediate_only)
20082008
void
20092009
DeferredTriggerInit(void)
20102010
{
2011-
/*
2012-
* Since this context will never be reset, give it a minsize of 0.
2013-
* This avoids using any memory if the session never stores anything.
2014-
*/
20152011
deftrig_gcxt = AllocSetContextCreate(TopMemoryContext,
20162012
"DeferredTriggerSession",
2017-
0,
2013+
ALLOCSET_DEFAULT_MINSIZE,
20182014
ALLOCSET_DEFAULT_INITSIZE,
20192015
ALLOCSET_DEFAULT_MAXSIZE);
20202016
}
@@ -2041,12 +2037,11 @@ DeferredTriggerBeginXact(void)
20412037

20422038
/*
20432039
* Create the per transaction memory context and copy all states from
2044-
* the per session context to here. Set the minsize to 0 to avoid
2045-
* wasting memory if there is no deferred trigger data.
2040+
* the per session context to here.
20462041
*/
20472042
deftrig_cxt = AllocSetContextCreate(TopTransactionContext,
20482043
"DeferredTriggerXact",
2049-
0,
2044+
ALLOCSET_DEFAULT_MINSIZE,
20502045
ALLOCSET_DEFAULT_INITSIZE,
20512046
ALLOCSET_DEFAULT_MAXSIZE);
20522047
oldcxt = MemoryContextSwitchTo(deftrig_cxt);

‎src/backend/executor/execJunk.c

Lines changed: 1 addition & 35 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/executor/execJunk.c,v 1.33 2002/12/12 15:49:28 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/executor/execJunk.c,v 1.34 2002/12/15 21:01:34 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -63,8 +63,6 @@ JunkFilter *
6363
ExecInitJunkFilter(List *targetList, TupleDesc tupType,
6464
TupleTableSlot *slot)
6565
{
66-
MemoryContext oldContext;
67-
MemoryContext junkContext;
6866
JunkFilter *junkfilter;
6967
List *cleanTargetList;
7068
int len,
@@ -79,19 +77,6 @@ ExecInitJunkFilter(List *targetList, TupleDesc tupType,
7977
AttrNumber *cleanMap;
8078
Expr *expr;
8179

82-
/*
83-
* Make a memory context that will hold the JunkFilter as well as all
84-
* the subsidiary structures we are about to create. We use smaller-
85-
* than-default sizing parameters since we don't expect a very large
86-
* volume of stuff here.
87-
*/
88-
junkContext = AllocSetContextCreate(CurrentMemoryContext,
89-
"JunkFilterContext",
90-
1024,
91-
1024,
92-
ALLOCSET_DEFAULT_MAXSIZE);
93-
oldContext = MemoryContextSwitchTo(junkContext);
94-
9580
/*
9681
* First find the "clean" target list, i.e. all the entries in the
9782
* original target list which have a false 'resjunk' NOTE: make copy
@@ -174,33 +159,14 @@ ExecInitJunkFilter(List *targetList, TupleDesc tupType,
174159
junkfilter->jf_cleanLength = cleanLength;
175160
junkfilter->jf_cleanTupType = cleanTupType;
176161
junkfilter->jf_cleanMap = cleanMap;
177-
junkfilter->jf_junkContext = junkContext;
178162
junkfilter->jf_resultSlot = slot;
179163

180164
if (slot)
181165
ExecSetSlotDescriptor(slot, cleanTupType, false);
182166

183-
MemoryContextSwitchTo(oldContext);
184-
185167
return junkfilter;
186168
}
187169

188-
/*-------------------------------------------------------------------------
189-
* ExecFreeJunkFilter
190-
*
191-
* Release the data structures created by ExecInitJunkFilter.
192-
*-------------------------------------------------------------------------
193-
*/
194-
void
195-
ExecFreeJunkFilter(JunkFilter *junkfilter)
196-
{
197-
/*
198-
* Since the junkfilter is inside its own context, we just have to
199-
* delete the context and we're set.
200-
*/
201-
MemoryContextDelete(junkfilter->jf_junkContext);
202-
}
203-
204170
/*-------------------------------------------------------------------------
205171
* ExecGetJunkAttribute
206172
*

‎src/backend/executor/execMain.c

Lines changed: 8 additions & 15 deletions
Original file line numberDiff line numberDiff line change
@@ -26,7 +26,7 @@
2626
*
2727
*
2828
* IDENTIFICATION
29-
* $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.193 2002/12/15 16:17:45 tgl Exp $
29+
* $Header: /cvsroot/pgsql/src/backend/executor/execMain.c,v 1.194 2002/12/15 21:01:34 tgl Exp $
3030
*
3131
*-------------------------------------------------------------------------
3232
*/
@@ -775,6 +775,12 @@ initResultRelInfo(ResultRelInfo *resultRelInfo,
775775
* ExecEndPlan
776776
*
777777
* Cleans up the query plan -- closes files and frees up storage
778+
*
779+
* NOTE: we are no longer very worried about freeing storage per se
780+
* in this code; FreeExecutorState should be guaranteed to release all
781+
* memory that needs to be released. What we are worried about doing
782+
* is closing relations and dropping buffer pins. Thus, for example,
783+
* tuple tables must be cleared or dropped to ensure pins are released.
778784
* ----------------------------------------------------------------
779785
*/
780786
void
@@ -803,17 +809,14 @@ ExecEndPlan(PlanState *planstate, EState *estate)
803809

804810
/*
805811
* close the result relation(s) if any, but hold locks until xact
806-
* commit. Also clean up junkfilters if present.
812+
* commit.
807813
*/
808814
resultRelInfo = estate->es_result_relations;
809815
for (i = estate->es_num_result_relations; i > 0; i--)
810816
{
811817
/* Close indices and then the relation itself */
812818
ExecCloseIndices(resultRelInfo);
813819
heap_close(resultRelInfo->ri_RelationDesc, NoLock);
814-
/* Delete the junkfilter if any */
815-
if (resultRelInfo->ri_junkFilter != NULL)
816-
ExecFreeJunkFilter(resultRelInfo->ri_junkFilter);
817820
resultRelInfo++;
818821
}
819822

@@ -823,16 +826,6 @@ ExecEndPlan(PlanState *planstate, EState *estate)
823826
if (estate->es_into_relation_descriptor != NULL)
824827
heap_close(estate->es_into_relation_descriptor, NoLock);
825828

826-
/*
827-
* There might be a junkfilter without a result relation.
828-
*/
829-
if (estate->es_num_result_relations == 0 &&
830-
estate->es_junkFilter != NULL)
831-
{
832-
ExecFreeJunkFilter(estate->es_junkFilter);
833-
estate->es_junkFilter = NULL;
834-
}
835-
836829
/*
837830
* close any relations selected FOR UPDATE, again keeping locks
838831
*/

‎src/backend/executor/spi.c

Lines changed: 4 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/executor/spi.c,v 1.80 2002/12/15 16:17:46 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/executor/spi.c,v 1.81 2002/12/15 21:01:34 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -1489,9 +1489,9 @@ _SPI_copy_plan(_SPI_plan *plan, int location)
14891489
*/
14901490
plancxt = AllocSetContextCreate(parentcxt,
14911491
"SPI Plan",
1492-
1024,
1493-
1024,
1494-
ALLOCSET_DEFAULT_MAXSIZE);
1492+
ALLOCSET_SMALL_MINSIZE,
1493+
ALLOCSET_SMALL_INITSIZE,
1494+
ALLOCSET_SMALL_MAXSIZE);
14951495
oldcxt = MemoryContextSwitchTo(plancxt);
14961496

14971497
/* Copy the SPI plan into its own context */

‎src/backend/utils/cache/relcache.c

Lines changed: 10 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/utils/cache/relcache.c,v 1.181 2002/11/15 17:18:49 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/utils/cache/relcache.c,v 1.182 2002/12/15 21:01:34 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -647,9 +647,9 @@ RelationBuildRuleLock(Relation relation)
647647
*/
648648
rulescxt = AllocSetContextCreate(CacheMemoryContext,
649649
RelationGetRelationName(relation),
650-
0, /* minsize */
651-
1024, /* initsize */
652-
1024); /* maxsize */
650+
ALLOCSET_SMALL_MINSIZE,
651+
ALLOCSET_SMALL_INITSIZE,
652+
ALLOCSET_SMALL_MAXSIZE);
653653
relation->rd_rulescxt = rulescxt;
654654

655655
/*
@@ -994,9 +994,9 @@ RelationInitIndexAccessInfo(Relation relation)
994994
*/
995995
indexcxt = AllocSetContextCreate(CacheMemoryContext,
996996
RelationGetRelationName(relation),
997-
0, /* minsize */
998-
512, /* initsize */
999-
1024); /* maxsize */
997+
ALLOCSET_SMALL_MINSIZE,
998+
ALLOCSET_SMALL_INITSIZE,
999+
ALLOCSET_SMALL_MAXSIZE);
10001000
relation->rd_indexcxt = indexcxt;
10011001

10021002
/*
@@ -2851,9 +2851,9 @@ load_relcache_init_file(void)
28512851
*/
28522852
indexcxt = AllocSetContextCreate(CacheMemoryContext,
28532853
RelationGetRelationName(rel),
2854-
0, /* minsize */
2855-
512, /* initsize */
2856-
1024); /* maxsize */
2854+
ALLOCSET_SMALL_MINSIZE,
2855+
ALLOCSET_SMALL_INITSIZE,
2856+
ALLOCSET_SMALL_MAXSIZE);
28572857
rel->rd_indexcxt = indexcxt;
28582858

28592859
/* next, read the index strategy map */

‎src/backend/utils/mmgr/aset.c

Lines changed: 21 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -11,7 +11,7 @@
1111
* Portions Copyright (c) 1994, Regents of the University of California
1212
*
1313
* IDENTIFICATION
14-
* $Header: /cvsroot/pgsql/src/backend/utils/mmgr/aset.c,v 1.48 2002/09/04 20:31:33 momjian Exp $
14+
* $Header: /cvsroot/pgsql/src/backend/utils/mmgr/aset.c,v 1.49 2002/12/15 21:01:34 tgl Exp $
1515
*
1616
* NOTE:
1717
* This is a new (Feb. 05, 1999) implementation of the allocation set
@@ -371,10 +371,11 @@ AllocSetInit(MemoryContext context)
371371
* Frees all memory which is allocated in the given set.
372372
*
373373
* Actually, this routine has some discretion about what to do.
374-
* It should mark all allocated chunks freed, but it need not
375-
* necessarily give back all the resources the set owns. Our
376-
* actual implementation is that we hang on to any "keeper"
377-
* block specified for the set.
374+
* It should mark all allocated chunks freed, but it need not necessarily
375+
* give back all the resources the set owns. Our actual implementation is
376+
* that we hang onto any "keeper" block specified for the set. In this way,
377+
* we don't thrash malloc() when a context is repeatedly reset after small
378+
* allocations, which is typical behavior for per-tuple contexts.
378379
*/
379380
static void
380381
AllocSetReset(MemoryContext context)
@@ -697,6 +698,21 @@ AllocSetAlloc(MemoryContext context, Size size)
697698
block->freeptr = ((char *) block) + ALLOC_BLOCKHDRSZ;
698699
block->endptr = ((char *) block) + blksize;
699700

701+
/*
702+
* If this is the first block of the set, make it the "keeper" block.
703+
* Formerly, a keeper block could only be created during context
704+
* creation, but allowing it to happen here lets us have fast reset
705+
* cycling even for contexts created with minContextSize = 0; that
706+
* way we don't have to force space to be allocated in contexts that
707+
* might never need any space. Don't mark an oversize block as
708+
* a keeper, however.
709+
*/
710+
if (set->blocks == NULL && blksize == set->initBlockSize)
711+
{
712+
Assert(set->keeper == NULL);
713+
set->keeper = block;
714+
}
715+
700716
block->next = set->blocks;
701717
set->blocks = block;
702718
}

‎src/backend/utils/mmgr/mcxt.c

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -14,7 +14,7 @@
1414
*
1515
*
1616
* IDENTIFICATION
17-
* $Header: /cvsroot/pgsql/src/backend/utils/mmgr/mcxt.c,v 1.36 2002/11/13 00:37:06 momjian Exp $
17+
* $Header: /cvsroot/pgsql/src/backend/utils/mmgr/mcxt.c,v 1.37 2002/12/15 21:01:34 tgl Exp $
1818
*
1919
*-------------------------------------------------------------------------
2020
*/
@@ -80,7 +80,7 @@ MemoryContextInit(void)
8080
*/
8181
TopMemoryContext = AllocSetContextCreate((MemoryContext) NULL,
8282
"TopMemoryContext",
83-
8 * 1024,
83+
0,
8484
8 * 1024,
8585
8 * 1024);
8686

‎src/include/executor/executor.h

Lines changed: 1 addition & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
88
* Portions Copyright (c) 1994, Regents of the University of California
99
*
10-
* $Id: executor.h,v 1.84 2002/12/15 16:17:54 tgl Exp $
10+
* $Id: executor.h,v 1.85 2002/12/15 21:01:34 tgl Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -41,7 +41,6 @@ extern bool ExecSupportsMarkRestore(NodeTag plantype);
4141
*/
4242
extern JunkFilter *ExecInitJunkFilter(List *targetList, TupleDesc tupType,
4343
TupleTableSlot *slot);
44-
extern void ExecFreeJunkFilter(JunkFilter *junkfilter);
4544
extern bool ExecGetJunkAttribute(JunkFilter *junkfilter, TupleTableSlot *slot,
4645
char *attrName, Datum *value, bool *isNull);
4746
extern HeapTuple ExecRemoveJunk(JunkFilter *junkfilter, TupleTableSlot *slot);

‎src/include/nodes/execnodes.h

Lines changed: 1 addition & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
* Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
88
* Portions Copyright (c) 1994, Regents of the University of California
99
*
10-
* $Id: execnodes.h,v 1.86 2002/12/15 16:17:56 tgl Exp $
10+
* $Id: execnodes.h,v 1.87 2002/12/15 21:01:34 tgl Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -218,16 +218,7 @@ typedef struct ProjectionInfo
218218
* cleanMap: A map with the correspondence between the non-junk
219219
* attribute numbers of the "original" tuple and the
220220
* attribute numbers of the "clean" tuple.
221-
* junkContext: memory context holding the JunkFilter node and all
222-
* its subsidiary data structures.
223221
* resultSlot: tuple slot that can be used to hold cleaned tuple.
224-
*
225-
* NOTE: the original targetList and tupType are passed to ExecInitJunkFilter,
226-
* as is the resultSlot. These items do not belong to the JunkFilter. All
227-
* the other subsidiary structures are created during ExecInitJunkFilter,
228-
* and all of them can be freed by deleting the memory context junkContext.
229-
* This would not be needed if we had a cleaner approach to managing
230-
* query-lifetime data structures...
231222
* ----------------
232223
*/
233224
typedef struct JunkFilter
@@ -240,7 +231,6 @@ typedef struct JunkFilter
240231
int jf_cleanLength;
241232
TupleDesc jf_cleanTupType;
242233
AttrNumber *jf_cleanMap;
243-
MemoryContext jf_junkContext;
244234
TupleTableSlot *jf_resultSlot;
245235
} JunkFilter;
246236

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