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Commit60be6da

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committed
Replace nth() calls in inner loops with traversal of the list via
lnext, to eliminate O(N^2) behavior with lots of indexquals.
1 parent78296c2 commit60be6da

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1 file changed

+32
-28
lines changed

1 file changed

+32
-28
lines changed

‎src/backend/executor/nodeIndexscan.c

Lines changed: 32 additions & 28 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/executor/nodeIndexscan.c,v 1.45 2000/01/26 05:56:23 momjian Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/executor/nodeIndexscan.c,v 1.46 2000/02/05 23:19:44 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -124,7 +124,7 @@ IndexNext(IndexScan *node)
124124
if (estate->es_evTuple!=NULL&&
125125
estate->es_evTuple[node->scan.scanrelid-1]!=NULL)
126126
{
127-
intiptr;
127+
List*qual;
128128

129129
ExecClearTuple(slot);
130130
if (estate->es_evTupleNull[node->scan.scanrelid-1])
@@ -134,20 +134,23 @@ IndexNext(IndexScan *node)
134134
slot->val=estate->es_evTuple[node->scan.scanrelid-1];
135135
slot->ttc_shouldFree= false;
136136

137-
for (iptr=0;iptr<numIndices;iptr++)
137+
scanstate->cstate.cs_ExprContext->ecxt_scantuple=slot;
138+
139+
/* Does the tuple meet any of the OR'd indxqual conditions? */
140+
foreach(qual,node->indxqualorig)
138141
{
139-
scanstate->cstate.cs_ExprContext->ecxt_scantuple=slot;
140-
if (ExecQual(nth(iptr,node->indxqualorig),
142+
if (ExecQual((List*)lfirst(qual),
141143
scanstate->cstate.cs_ExprContext,
142144
false))
143145
break;
144146
}
145-
if (iptr==numIndices)/* would not be returned by indices */
147+
if (qual==NIL)/* would not be returned by indices */
146148
slot->val=NULL;
147149

148150
/* Flag for the next call that no more tuples */
149151
estate->es_evTupleNull[node->scan.scanrelid-1]= true;
150-
return (slot);
152+
153+
returnslot;
151154
}
152155

153156
tuple=&(indexstate->iss_htup);
@@ -189,14 +192,14 @@ IndexNext(IndexScan *node)
189192
{
190193
boolprev_matches= false;
191194
intprev_index;
195+
List*qual;
192196

193-
/* ----------------
197+
/*
194198
*store the scanned tuple in the scan tuple slot of
195199
*the scan state. Eventually we will only do this and not
196200
*return a tuple. Note: we pass 'false' because tuples
197201
*returned by amgetnext are pointers onto disk pages and
198202
*must not be pfree()'d.
199-
* ----------------
200203
*/
201204
ExecStoreTuple(tuple,/* tuple to store */
202205
slot,/* slot to store in */
@@ -211,28 +214,29 @@ IndexNext(IndexScan *node)
211214
ReleaseBuffer(buffer);
212215

213216
/*
214-
* We must check to see if the current tuple would have
215-
* been matched by an earlier index, so we don't double
216-
* report it. We do this by passing the tuple through
217-
* ExecQual and look for failure with all previous
218-
* qualifications.
217+
* We must check to see if the current tuple was already
218+
* matched by an earlier index, so we don't double-report it.
219+
* We do this by passing the tuple through ExecQual and
220+
* checking for failure with all previous qualifications.
219221
*/
222+
scanstate->cstate.cs_ExprContext->ecxt_scantuple=slot;
223+
qual=node->indxqualorig;
220224
for (prev_index=0;prev_index<indexstate->iss_IndexPtr;
221225
prev_index++)
222226
{
223-
scanstate->cstate.cs_ExprContext->ecxt_scantuple=slot;
224-
if (ExecQual(nth(prev_index,node->indxqualorig),
227+
if (ExecQual((List*)lfirst(qual),
225228
scanstate->cstate.cs_ExprContext,
226229
false))
227230
{
228231
prev_matches= true;
229232
break;
230233
}
234+
qual=lnext(qual);
231235
}
232236
if (!prev_matches)
233-
returnslot;
234-
else
235-
ExecClearTuple(slot);
237+
returnslot;/* OK to return tuple */
238+
/* Duplicate tuple, so drop it and loop back for another */
239+
ExecClearTuple(slot);
236240
}
237241
}
238242
if (indexNumber<numIndices)
@@ -329,7 +333,6 @@ ExecIndexReScan(IndexScan *node, ExprContext *exprCtxt, Plan *parent)
329333
scanDescs=indexstate->iss_ScanDescs;
330334
scanKeys=indexstate->iss_ScanKeys;
331335
runtimeKeyInfo= (Pointer*)indexstate->iss_RuntimeKeyInfo;
332-
indxqual=node->indxqual;
333336
numScanKeys=indexstate->iss_NumScanKeys;
334337
indexstate->iss_IndexPtr=-1;
335338
if (ScanDirectionIsBackward(node->indxorderdir))
@@ -352,9 +355,11 @@ ExecIndexReScan(IndexScan *node, ExprContext *exprCtxt, Plan *parent)
352355
/*
353356
* get the index qualifications and recalculate the appropriate values
354357
*/
358+
indxqual=node->indxqual;
355359
for (i=0;i<numIndices;i++)
356360
{
357-
qual=nth(i,indxqual);
361+
qual=lfirst(indxqual);
362+
indxqual=lnext(indxqual);
358363
n_keys=numScanKeys[i];
359364
scan_keys= (ScanKey)scanKeys[i];
360365

@@ -672,7 +677,6 @@ ExecInitIndexScan(IndexScan *node, EState *estate, Plan *parent)
672677
* ----------------
673678
*/
674679
indxid=node->indxid;
675-
indxqual=node->indxqual;
676680
numIndices=length(indxid);
677681
indexPtr=-1;
678682

@@ -701,6 +705,7 @@ ExecInitIndexScan(IndexScan *node, EState *estate, Plan *parent)
701705
*build the index scan keys from the index qualification
702706
* ----------------
703707
*/
708+
indxqual=node->indxqual;
704709
for (i=0;i<numIndices;i++)
705710
{
706711
intj;
@@ -709,7 +714,8 @@ ExecInitIndexScan(IndexScan *node, EState *estate, Plan *parent)
709714
ScanKeyscan_keys;
710715
int*run_keys;
711716

712-
qual=nth(i,indxqual);
717+
qual=lfirst(indxqual);
718+
indxqual=lnext(indxqual);
713719
n_keys=length(qual);
714720
scan_keys= (n_keys <=0) ?NULL :
715721
(ScanKey)palloc(n_keys*sizeof(ScanKeyData));
@@ -743,8 +749,8 @@ ExecInitIndexScan(IndexScan *node, EState *estate, Plan *parent)
743749
clause=nth(j,qual);
744750

745751
op= (Oper*)clause->oper;
746-
if (!IsA(op,Oper))
747-
elog(ERROR,"ExecInitIndexScan:op not anOper!");
752+
if (!IsA(clause,Expr)|| !IsA(op,Oper))
753+
elog(ERROR,"ExecInitIndexScan:indxqual not anopclause!");
748754

749755
opid=op->opid;
750756

@@ -1066,9 +1072,7 @@ ExecInitIndexScan(IndexScan *node, EState *estate, Plan *parent)
10661072
*/
10671073
for (i=0;i<numIndices;i++)
10681074
{
1069-
OidindexOid;
1070-
1071-
indexOid= (Oid)nthi(i,indxid);
1075+
OidindexOid= (Oid)nthi(i,indxid);
10721076

10731077
if (indexOid!=0)
10741078
{

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