diff options
Diffstat (limited to 'src/backend/executor/nodeSort.c')
| -rw-r--r-- | src/backend/executor/nodeSort.c | 22 |
1 files changed, 19 insertions, 3 deletions
diff --git a/src/backend/executor/nodeSort.c b/src/backend/executor/nodeSort.c index 367adbfbe20..f799c78218a 100644 --- a/src/backend/executor/nodeSort.c +++ b/src/backend/executor/nodeSort.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/executor/nodeSort.c,v 1.54 2006/02/28 04:10:27 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/executor/nodeSort.c,v 1.55 2006/02/28 05:48:44 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -89,7 +89,7 @@ ExecSort(SortState *node) plannode->sortOperators, plannode->sortColIdx, work_mem, - true /* randomAccess */ ); + node->randomAccess); node->tuplesortstate = (void *) tuplesortstate; /* @@ -164,6 +164,15 @@ ExecInitSort(Sort *node, EState *estate, int eflags) sortstate->ss.ps.plan = (Plan *) node; sortstate->ss.ps.state = estate; + /* + * We must have random access to the sort output to do backward scan + * or mark/restore. We also prefer to materialize the sort output + * if we might be called on to rewind and replay it many times. + */ + sortstate->randomAccess = (eflags & (EXEC_FLAG_REWIND | + EXEC_FLAG_BACKWARD | + EXEC_FLAG_MARK)) != 0; + sortstate->sort_Done = false; sortstate->tuplesortstate = NULL; @@ -308,11 +317,18 @@ ExecReScanSort(SortState *node, ExprContext *exprCtxt) * * Otherwise we can just rewind and rescan the sorted output. */ - if (((PlanState *) node)->lefttree->chgParam != NULL) + if (((PlanState *) node)->lefttree->chgParam != NULL || + !node->randomAccess) { node->sort_Done = false; tuplesort_end((Tuplesortstate *) node->tuplesortstate); node->tuplesortstate = NULL; + /* + * if chgParam of subnode is not null then plan will be re-scanned by + * first ExecProcNode. + */ + if (((PlanState *) node)->lefttree->chgParam == NULL) + ExecReScan(((PlanState *) node)->lefttree, exprCtxt); } else tuplesort_rescan((Tuplesortstate *) node->tuplesortstate); |