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Fix dumb bug in tqueue.c

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When I wrote this code originally, the intention was to recompute the
remapinfo only when the tupledesc changes.  This presumably only
happens once per query, but I copied the design pattern from other
DestReceivers.  However, due to a silly oversight on my part,
tqueue->tupledesc never got set, leading to recomputation for every
tuple.

This should improve the performance of parallel scans that return a
significant number of tuples.

Report by Amit Kapila; patch by me, reviewed by him.
This commit is contained in:
Robert Haas
2015-11-18 08:25:33 -05:00
parent 5f10b7a604
commit adeee97486
1 changed files with 4 additions and 4 deletions
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8
src/backend/executor/tqueue.c
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@ -127,15 +127,15 @@ tqueueReceiveSlot(TupleTableSlot *slot, DestReceiver *self)
* new tupledesc. This is a strange test both because the executor really * new tupledesc. This is a strange test both because the executor really
* shouldn't change the tupledesc, and also because it would be unsafe if * shouldn't change the tupledesc, and also because it would be unsafe if
* the old tupledesc could be freed and a new one allocated at the same * the old tupledesc could be freed and a new one allocated at the same
* address. But since some very old code in printtup.c uses this test, we * address. But since some very old code in printtup.c uses a similar
* adopt it here as well. * test, we adopt it here as well.
*/ */
if (tqueue->tupledesc != tupledesc || if (tqueue->tupledesc != tupledesc)
tqueue->remapinfo->natts != tupledesc->natts)
{ {
if (tqueue->remapinfo != NULL) if (tqueue->remapinfo != NULL)
pfree(tqueue->remapinfo); pfree(tqueue->remapinfo);
tqueue->remapinfo = BuildRemapInfo(tupledesc); tqueue->remapinfo = BuildRemapInfo(tupledesc);
tqueue->tupledesc = tupledesc;
} }
tuple = ExecMaterializeSlot(slot); tuple = ExecMaterializeSlot(slot);