]> granicus.if.org Git - postgresql/commit
Don't allow LIMIT/OFFSET clause within sub-selects to be pushed to workers.
authorAmit Kapila <akapila@postgresql.org>
Fri, 14 Sep 2018 04:06:30 +0000 (09:36 +0530)
committerAmit Kapila <akapila@postgresql.org>
Fri, 14 Sep 2018 04:06:30 +0000 (09:36 +0530)
commit75f9c4ca5a8047d7a9cfbc7d51a610933d04dc7f
tree888a57df088ecaab838f08475d295ace7e30ae67
parent0ba06e0bfb8cfd24ff17aca92aa72245ddd6c4d7
Don't allow LIMIT/OFFSET clause within sub-selects to be pushed to workers.

Allowing sub-select containing LIMIT/OFFSET in workers can lead to
inconsistent results at the top-level as there is no guarantee that the
row order will be fully deterministic.  The fix is to prohibit pushing
LIMIT/OFFSET within sub-selects to workers.

Reported-by: Andrew Fletcher
Bug: 15324
Author: Amit Kapila
Reviewed-by: Dilip Kumar
Backpatch-through: 9.6
Discussion: https://postgr.es/m/153417684333.10284.11356259990921828616@wrigleys.postgresql.org
src/backend/optimizer/path/allpaths.c
src/backend/optimizer/plan/planner.c
src/include/optimizer/planner.h
src/test/regress/expected/select_parallel.out
src/test/regress/sql/select_parallel.sql