From adeee974866085db84b860c1f397dd7c6b136a0a Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Wed, 18 Nov 2015 08:25:33 -0500
Subject: [PATCH] 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.
---
src/backend/executor/tqueue.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/src/backend/executor/tqueue.c b/src/backend/executor/tqueue.c
index 5735acf10e3..d625b0d800b 100644
--- a/src/backend/executor/tqueue.c
+++ b/src/backend/executor/tqueue.c
@@ -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);
--
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