Fix dumb bug in tqueue.c

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

View File

@ -127,15 +127,15 @@ tqueueReceiveSlot(TupleTableSlot *slot, DestReceiver *self)
* 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
* 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
* adopt it here as well.
* address. But since some very old code in printtup.c uses a similar
* test, we adopt it here as well.
*/
if (tqueue->tupledesc != tupledesc ||
tqueue->remapinfo->natts != tupledesc->natts)
if (tqueue->tupledesc != tupledesc)
{
if (tqueue->remapinfo != NULL)
pfree(tqueue->remapinfo);
tqueue->remapinfo = BuildRemapInfo(tupledesc);
tqueue->tupledesc = tupledesc;
}
tuple = ExecMaterializeSlot(slot);