Horton

Fix usage of aggregate pathkeys in group_keys_reorder_by_pathkeys()

Alexander Korotkov <akorotkov@postgresql.org>

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Commit: c01f6ef46c8f0ab3faa54e8f040da6e9ddc7fe5b
Author: Alexander Korotkov <akorotkov@postgresql.org>
Date: 2024-02-09T10:56:54Z
Releases: 17.0 
Fix usage of aggregate pathkeys in group_keys_reorder_by_pathkeys()

group_keys_reorder_by_pathkeys() function searched for matching pathkeys
within root->group_pathkeys.  That could lead to picking an aggregate pathkey
and using its pathkey->pk_eclass->ec_sortref as an argument of
get_sortgroupref_clause_noerr().  Given that ec_sortref of an aggregate pathkey
references aggregate targetlist not query targetlist, this leads to incorrect
query optimization.

Fix this by looking for matching pathkeys only within the first
num_groupby_pathkeys pathkeys.

Reported-by: David G. Johnston
Discussion: https://postgr.es/m/CAKFQuwY3Ek%3DcLThgd8FdaSc5JRDVt0FaV00gMcWra%2BTAR4gGUw%40mail.gmail.com
Author: Andrei Lepikhov, Alexander Korotkov

Files

PathChange+/−
src/backend/optimizer/path/pathkeys.c modified +21 −4
src/test/regress/expected/aggregates.out modified +24 −0
src/test/regress/sql/aggregates.sql modified +19 −0

Discussion