From 75f9c4ca5a8047d7a9cfbc7d51a610933d04dc7f Mon Sep 17 00:00:00 2001 From: Amit Kapila Date: Fri, 14 Sep 2018 09:36:30 +0530 Subject: 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/test/regress/sql/select_parallel.sql | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'src/test/regress/sql/select_parallel.sql') diff --git a/src/test/regress/sql/select_parallel.sql b/src/test/regress/sql/select_parallel.sql index 3d1dffe61d2..938c708d18f 100644 --- a/src/test/regress/sql/select_parallel.sql +++ b/src/test/regress/sql/select_parallel.sql @@ -368,6 +368,11 @@ explain (costs off, verbose) (select unique1, row_number() over() from tenk1 b); +-- LIMIT/OFFSET within sub-selects can't be pushed to workers. +explain (costs off) + select * from tenk1 a where two in + (select two from tenk1 b where stringu1 like '%AAAA' limit 3); + -- to increase the parallel query test coverage SAVEPOINT settings; SET LOCAL force_parallel_mode = 1; -- cgit v1.2.3