• Tom Lane's avatar
    Fix EquivalenceClass processing for nested append relations. · a87c7291
    Tom Lane authored
    The original coding of EquivalenceClasses didn't foresee that appendrel
    child relations might themselves be appendrels; but this is possible for
    example when a UNION ALL subquery scans a table with inheritance children.
    The oversight led to failure to optimize ordering-related issues very well
    for the grandchild tables.  After some false starts involving explicitly
    flattening the appendrel representation, we found that this could be fixed
    easily by removing a few implicit assumptions about appendrel parent rels
    not being children themselves.
    
    Kyotaro Horiguchi and Tom Lane, reviewed by Noah Misch
    a87c7291
createplan.c 140 KB