diff options
Diffstat (limited to 'src/backend/executor/nodeUnique.c')
| -rw-r--r-- | src/backend/executor/nodeUnique.c | 45 |
1 files changed, 7 insertions, 38 deletions
diff --git a/src/backend/executor/nodeUnique.c b/src/backend/executor/nodeUnique.c index dbd628ba878..10ffddd5cdf 100644 --- a/src/backend/executor/nodeUnique.c +++ b/src/backend/executor/nodeUnique.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/executor/nodeUnique.c,v 1.45 2004/12/31 21:59:45 pgsql Exp $ + * $PostgreSQL: pgsql/src/backend/executor/nodeUnique.c,v 1.46 2005/03/16 21:38:08 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -44,14 +44,12 @@ ExecUnique(UniqueState *node) TupleTableSlot *resultTupleSlot; TupleTableSlot *slot; PlanState *outerPlan; - TupleDesc tupDesc; /* * get information from the node */ outerPlan = outerPlanState(node); resultTupleSlot = node->ps.ps_ResultTupleSlot; - tupDesc = ExecGetResultType(&node->ps); /* * now loop, returning only non-duplicate tuples. We assume that the @@ -59,7 +57,7 @@ ExecUnique(UniqueState *node) * * We return the first tuple from each group of duplicates (or the last * tuple of each group, when moving backwards). At either end of the - * subplan, clear priorTuple so that we correctly return the + * subplan, clear the result slot so that we correctly return the * first/last tuple when reversing direction. */ for (;;) @@ -71,16 +69,14 @@ ExecUnique(UniqueState *node) if (TupIsNull(slot)) { /* end of subplan; reset in case we change direction */ - if (node->priorTuple != NULL) - heap_freetuple(node->priorTuple); - node->priorTuple = NULL; + ExecClearTuple(resultTupleSlot); return NULL; } /* * Always return the first/last tuple from the subplan. */ - if (node->priorTuple == NULL) + if (TupIsNull(resultTupleSlot)) break; /* @@ -88,8 +84,7 @@ ExecUnique(UniqueState *node) * match. If so then we loop back and fetch another new tuple * from the subplan. */ - if (!execTuplesMatch(slot->val, node->priorTuple, - tupDesc, + if (!execTuplesMatch(slot, resultTupleSlot, plannode->numCols, plannode->uniqColIdx, node->eqfunctions, node->tempContext)) @@ -101,28 +96,8 @@ ExecUnique(UniqueState *node) * any). Save it and return it. We must copy it because the source * subplan won't guarantee that this source tuple is still accessible * after fetching the next source tuple. - * - * Note that we manage the copy ourselves. We can't rely on the result - * tuple slot to maintain the tuple reference because our caller may - * replace the slot contents with a different tuple. We assume that - * the caller will no longer be interested in the current tuple after - * he next calls us. - * - * tgl 3/2004: the above concern is no longer valid; junkfilters used to - * modify their input's return slot but don't anymore, and I don't - * think anyplace else does either. Not worth changing this code - * though. */ - if (node->priorTuple != NULL) - heap_freetuple(node->priorTuple); - node->priorTuple = heap_copytuple(slot->val); - - ExecStoreTuple(node->priorTuple, - resultTupleSlot, - InvalidBuffer, - false); /* tuple does not belong to slot */ - - return resultTupleSlot; + return ExecCopySlot(resultTupleSlot, slot); } /* ---------------------------------------------------------------- @@ -144,8 +119,6 @@ ExecInitUnique(Unique *node, EState *estate) uniquestate->ps.plan = (Plan *) node; uniquestate->ps.state = estate; - uniquestate->priorTuple = NULL; - /* * Miscellaneous initialization * @@ -220,12 +193,8 @@ ExecEndUnique(UniqueState *node) void ExecReScanUnique(UniqueState *node, ExprContext *exprCtxt) { + /* must clear result tuple so first input tuple is returned */ ExecClearTuple(node->ps.ps_ResultTupleSlot); - if (node->priorTuple != NULL) - { - heap_freetuple(node->priorTuple); - node->priorTuple = NULL; - } /* * if chgParam of subnode is not null then plan will be re-scanned by |