diff options
Diffstat (limited to 'src/backend/executor/nodeAgg.c')
| -rw-r--r-- | src/backend/executor/nodeAgg.c | 33 |
1 files changed, 31 insertions, 2 deletions
diff --git a/src/backend/executor/nodeAgg.c b/src/backend/executor/nodeAgg.c index bbdda3540a7..603df5ed1c4 100644 --- a/src/backend/executor/nodeAgg.c +++ b/src/backend/executor/nodeAgg.c @@ -45,7 +45,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/executor/nodeAgg.c,v 1.104 2003/02/09 00:30:39 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/executor/nodeAgg.c,v 1.105 2003/05/30 20:23:10 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -1374,6 +1374,31 @@ ExecReScanAgg(AggState *node, ExprContext *exprCtxt) ExprContext *econtext = node->ss.ps.ps_ExprContext; int aggno; + node->agg_done = false; + + if (((Agg *) node->ss.ps.plan)->aggstrategy == AGG_HASHED) + { + /* + * In the hashed case, if we haven't yet built the hash table + * then we can just return; nothing done yet, so nothing to undo. + * If subnode's chgParam is not NULL then it will be re-scanned by + * ExecProcNode, else no reason to re-scan it at all. + */ + if (!node->table_filled) + return; + + /* + * If we do have the hash table and the subplan does not have any + * parameter changes, then we can just rescan the existing hash + * table; no need to build it again. + */ + if (((PlanState *) node)->lefttree->chgParam == NULL) + { + ResetTupleHashIterator(&node->hashiter); + return; + } + } + /* Make sure we have closed any open tuplesorts */ for (aggno = 0; aggno < node->numaggs; aggno++) { @@ -1384,19 +1409,23 @@ ExecReScanAgg(AggState *node, ExprContext *exprCtxt) peraggstate->sortstate = NULL; } - node->agg_done = false; + /* Release first tuple of group, if we have made a copy */ if (node->grp_firstTuple != NULL) { heap_freetuple(node->grp_firstTuple); node->grp_firstTuple = NULL; } + + /* Forget current agg values */ MemSet(econtext->ecxt_aggvalues, 0, sizeof(Datum) * node->numaggs); MemSet(econtext->ecxt_aggnulls, 0, sizeof(bool) * node->numaggs); + /* Release all temp storage */ MemoryContextReset(node->aggcontext); if (((Agg *) node->ss.ps.plan)->aggstrategy == AGG_HASHED) { + /* Rebuild an empty hash table */ build_hash_table(node); node->table_filled = false; } |