Fix wrong unsafe-flag test in check_output_expressions() The check for window functions (point 4) guarded on the wrong bit: it tested UNSAFE_NOTIN_DISTINCTON_CLAUSE while setting UNSAFE_NOTIN_PARTITIONBY_CLAUSE. Each check in this loop guards on the same bit it is about to set, as an idempotency optimization, since unsafeFlags[] is accumulated across the arms of a set operation and there is no point recomputing a column's status once its bit is present.
This is not a live bug. When UNSAFE_NOTIN_PARTITIONBY_CLAUSE is already set but UNSAFE_NOTIN_DISTINCTON_CLAUSE is not, the guard fails to skip targetIsInAllPartitionLists() and recomputes it, but setting the same bit again changes nothing. When UNSAFE_NOTIN_DISTINCTON_CLAUSE is already set, point 4 is skipped and UNSAFE_NOTIN_PARTITIONBY_CLAUSE is left unset; but such a column is already unsafe for pushdown via UNSAFE_NOTIN_DISTINCTON_CLAUSE, so the outcome is unchanged. To fix, test UNSAFE_NOTIN_PARTITIONBY_CLAUSE, matching the bit being set and the pattern of the surrounding checks. Back-patch to v15, where the buggy check was introduced. Author: Richard Guo <[email protected]> Reviewed-by: Tender Wang <[email protected]> Reviewed-by: David Rowley <[email protected]> Discussion: https://postgr.es/m/cambws49q_xnf_p2qsuydzj34mnro7dh-cuaak2hjpgsgh88...@mail.gmail.com Backpatch-through: 15 Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/ee2fa291c8b2f8abdbad57024b92652ac4a640ff Modified Files -------------- src/backend/optimizer/path/allpaths.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
