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| author | Amit Kapila <akapila@postgresql.org> | 2018-09-14 09:36:30 +0530 |
|---|---|---|
| committer | Amit Kapila <akapila@postgresql.org> | 2018-09-14 09:36:30 +0530 |
| commit | 75f9c4ca5a8047d7a9cfbc7d51a610933d04dc7f (patch) | |
| tree | 888a57df088ecaab838f08475d295ace7e30ae67 /src/test/regress/sql/select_parallel.sql | |
| parent | 0ba06e0bfb8cfd24ff17aca92aa72245ddd6c4d7 (diff) | |
| download | postgresql-75f9c4ca5a8047d7a9cfbc7d51a610933d04dc7f.tar.gz postgresql-75f9c4ca5a8047d7a9cfbc7d51a610933d04dc7f.zip | |
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
Diffstat (limited to 'src/test/regress/sql/select_parallel.sql')
| -rw-r--r-- | src/test/regress/sql/select_parallel.sql | 5 |
1 files changed, 5 insertions, 0 deletions
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; |