pgsql: Fix dumb bug in tqueue.c

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.

Branch
------
master

Details
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http://git.postgresql.org/pg/commitdiff/adeee974866085db84b860c1f397dd7c6b136a0a

Modified Files
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src/backend/executor/tqueue.c |    8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)