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Commitdb70a31

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Adjust nodeBitmapIndexscan to keep the target index opened from plan
startup to end, rather than re-opening it in each MultiExecBitmapIndexScancall. I had foolishly thought that opening/closing wouldn't be muchmore expensive than a rescan call, but that was sheer brain fade.This seems to fix about half of the performance lossage reported bySergey Koposov. I'm still not sure where the other half went.
1 parente6e7e64 commitdb70a31

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2 files changed

+48
-30
lines changed

2 files changed

+48
-30
lines changed

‎src/backend/executor/nodeBitmapIndexscan.c‎

Lines changed: 43 additions & 29 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/executor/nodeBitmapIndexscan.c,v 1.7 2005/04/25 01:30:12 tgl Exp $
11+
* $PostgreSQL: pgsql/src/backend/executor/nodeBitmapIndexscan.c,v 1.8 2005/05/05 03:37:23 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -38,8 +38,6 @@ MultiExecBitmapIndexScan(BitmapIndexScanState *node)
3838
{
3939
#defineMAX_TIDS1024
4040
TIDBitmap*tbm;
41-
Oidindexid;
42-
RelationindexRelation;
4341
IndexScanDescscandesc;
4442
ItemPointerDatatids[MAX_TIDS];
4543
int32ntids;
@@ -49,31 +47,18 @@ MultiExecBitmapIndexScan(BitmapIndexScanState *node)
4947
if (node->ss.ps.instrument)
5048
InstrStartNode(node->ss.ps.instrument);
5149

50+
/*
51+
* extract necessary information from index scan node
52+
*/
53+
scandesc=node->biss_ScanDesc;
54+
5255
/*
5356
* If we have runtime keys and they've not already been set up, do it
5457
* now.
5558
*/
5659
if (node->biss_RuntimeKeyInfo&& !node->biss_RuntimeKeysReady)
5760
ExecReScan((PlanState*)node,NULL);
5861

59-
/*
60-
* We do not open or lock the base relation here. We assume that an
61-
* ancestor BitmapHeapScan node is holding AccessShareLock on the
62-
* heap relation throughout the execution of the plan tree.
63-
*/
64-
65-
/*
66-
* open the index relation and initialize relation and scan
67-
* descriptors. Note we acquire no locks here; the index machinery
68-
* does its own locks and unlocks.
69-
*/
70-
indexid= ((BitmapIndexScan*)node->ss.ps.plan)->indexid;
71-
indexRelation=index_open(indexid);
72-
scandesc=index_beginscan_multi(indexRelation,
73-
node->ss.ps.state->es_snapshot,
74-
node->biss_NumScanKeys,
75-
node->biss_ScanKeys);
76-
7762
/*
7863
* Prepare the result bitmap. Normally we just create a new one to pass
7964
* back; however, our parent node is allowed to store a pre-made one
@@ -110,12 +95,6 @@ MultiExecBitmapIndexScan(BitmapIndexScanState *node)
11095
CHECK_FOR_INTERRUPTS();
11196
}
11297

113-
/*
114-
* close the index relation
115-
*/
116-
index_endscan(scandesc);
117-
index_close(indexRelation);
118-
11998
/* must provide our own instrumentation support */
12099
if (node->ss.ps.instrument)
121100
InstrStopNodeMulti(node->ss.ps.instrument,nTuples);
@@ -127,7 +106,7 @@ MultiExecBitmapIndexScan(BitmapIndexScanState *node)
127106
*ExecBitmapIndexReScan(node)
128107
*
129108
*Recalculates the value of the scan keys whose value depends on
130-
*information known at runtime.
109+
*information known at runtime and rescans the indexed relation.
131110
* ----------------------------------------------------------------
132111
*/
133112
void
@@ -169,6 +148,9 @@ ExecBitmapIndexReScan(BitmapIndexScanState *node, ExprContext *exprCtxt)
169148
node->biss_NumScanKeys);
170149
node->biss_RuntimeKeysReady= true;
171150
}
151+
152+
/* reset index scan */
153+
index_rescan(node->biss_ScanDesc,node->biss_ScanKeys);
172154
}
173155

174156
/* ----------------------------------------------------------------
@@ -178,13 +160,28 @@ ExecBitmapIndexReScan(BitmapIndexScanState *node, ExprContext *exprCtxt)
178160
void
179161
ExecEndBitmapIndexScan(BitmapIndexScanState*node)
180162
{
163+
RelationindexRelationDesc;
164+
IndexScanDescindexScanDesc;
165+
166+
/*
167+
* extract information from the node
168+
*/
169+
indexRelationDesc=node->biss_RelationDesc;
170+
indexScanDesc=node->biss_ScanDesc;
171+
181172
/*
182173
* Free the exprcontext ... now dead code, see ExecFreeExprContext
183174
*/
184175
#ifdefNOT_USED
185176
if (node->biss_RuntimeContext)
186177
FreeExprContext(node->biss_RuntimeContext);
187178
#endif
179+
180+
/*
181+
* close the index relation
182+
*/
183+
index_endscan(indexScanDesc);
184+
index_close(indexRelationDesc);
188185
}
189186

190187
/* ----------------------------------------------------------------
@@ -272,10 +269,27 @@ ExecInitBitmapIndexScan(BitmapIndexScan *node, EState *estate)
272269
indexstate->biss_RuntimeContext=NULL;
273270
}
274271

275-
/* We don't keep the table or index open across calls */
272+
/*
273+
* We do not open or lock the base relation here. We assume that an
274+
* ancestor BitmapHeapScan node is holding AccessShareLock on the
275+
* heap relation throughout the execution of the plan tree.
276+
*/
277+
276278
indexstate->ss.ss_currentRelation=NULL;
277279
indexstate->ss.ss_currentScanDesc=NULL;
278280

281+
/*
282+
* open the index relation and initialize relation and scan
283+
* descriptors. Note we acquire no locks here; the index machinery
284+
* does its own locks and unlocks.
285+
*/
286+
indexstate->biss_RelationDesc=index_open(node->indexid);
287+
indexstate->biss_ScanDesc=
288+
index_beginscan_multi(indexstate->biss_RelationDesc,
289+
estate->es_snapshot,
290+
numScanKeys,
291+
scanKeys);
292+
279293
/*
280294
* all done.
281295
*/

‎src/include/nodes/execnodes.h‎

Lines changed: 5 additions & 1 deletion
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/nodes/execnodes.h,v 1.130 2005/04/28 21:47:17 tgl Exp $
10+
* $PostgreSQL: pgsql/src/include/nodes/execnodes.h,v 1.131 2005/05/05 03:37:23 tgl Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -897,6 +897,8 @@ typedef struct IndexScanState
897897
* that will be evaluated at runtime
898898
*RuntimeContext expr context for evaling runtime Skeys
899899
*RuntimeKeysReady true if runtime Skeys have been computed
900+
*RelationDesc index relation descriptor
901+
*ScanDesc index scan descriptor
900902
* ----------------
901903
*/
902904
typedefstructBitmapIndexScanState
@@ -908,6 +910,8 @@ typedef struct BitmapIndexScanState
908910
ExprState**biss_RuntimeKeyInfo;
909911
ExprContext*biss_RuntimeContext;
910912
boolbiss_RuntimeKeysReady;
913+
Relationbiss_RelationDesc;
914+
IndexScanDescbiss_ScanDesc;
911915
}BitmapIndexScanState;
912916

913917
/* ----------------

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