postgres-github.git / summary / log / commit / refs

commit    ee2fa291c8b2f8abdbad57024b92652ac4a640ff
Author:   Richard Guo <rguo@postgresql.org>
Date:     Wed Jun 03 00:36:52 2026 +0000

    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 <guofenglinux@gmail.com>
    Reviewed-by: Tender Wang <tndrwang@gmail.com>
    Reviewed-by: David Rowley <dgrowleyml@gmail.com>
    Discussion: https://postgr.es/m/CAMbWs49Q_xnF_P2QSUyDzJ34MnrO7dh-cUAaK2HJPgSgh88NcA@mail.gmail.com
    Backpatch-through: 15

[parent: d21604e17e49]