]> granicus.if.org Git - postgresql/commit
Prohibit pushing subqueries containing window function calculation to
authorAmit Kapila <akapila@postgresql.org>
Tue, 4 Sep 2018 04:56:06 +0000 (10:26 +0530)
committerAmit Kapila <akapila@postgresql.org>
Tue, 4 Sep 2018 04:56:06 +0000 (10:26 +0530)
commit2ce253cf57b1c3f8100a31f30647449d0b88fe24
treef3fcff80b01121ae51fecacd2517f6a69cf9d20f
parent16e7bcfac57fc21dd2124b39132c58971e41448a
Prohibit pushing subqueries containing window function calculation to
workers.

Allowing window function calculation in workers leads to inconsistent
results because if the input row ordering is not fully deterministic, the
output of window functions might vary across workers.  The fix is to treat
them as parallel-restricted.

In the passing, improve the coding pattern in max_parallel_hazard_walker
so that it has a chain of mutually-exclusive if ... else if ... else if
... else if ... IsA tests.

Reported-by: Marko Tiikkaja
Bug: 15324
Author: Amit Kapila
Reviewed-by: Tom Lane
Backpatch-through: 9.6
Discussion: https://postgr.es/m/CAL9smLAnfPJCDUUG4ckX2iznj53V7VSMsYefzZieN93YxTNOcw@mail.gmail.com
src/backend/optimizer/util/clauses.c
src/test/regress/expected/select_parallel.out
src/test/regress/sql/select_parallel.sql