pgsql: Prevent Parallel Hash Join for JOIN_UNIQUE_INNER. - Mailing list pgsql-committers

From Thomas Munro
Subject pgsql: Prevent Parallel Hash Join for JOIN_UNIQUE_INNER.
Date
Msg-id E1hdEyI-0008Oe-7K@gemulon.postgresql.org
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Prevent Parallel Hash Join for JOIN_UNIQUE_INNER.

WHERE EXISTS (...) queries cannot be executed by Parallel Hash Join
with jointype JOIN_UNIQUE_INNER, because there is no way to make a
partial plan totally unique.  The consequence of allowing such plans
was duplicate results from some EXISTS queries.

Back-patch to 11.  Bug #15857.

Author: Thomas Munro
Reviewed-by: Tom Lane
Reported-by: Vladimir Kriukov
Discussion: https://postgr.es/m/15857-d1ba2a64bce0795e%40postgresql.org

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/aca127c105aae551620d607e88d76930e6b9a2cf

Modified Files
--------------
src/backend/optimizer/path/joinpath.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)


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