index fc3709510d2c673b5a299fc52db745c1f071cc7a..4bb68ac90e7d6223936b548e25537567e9903aba 100644 (file)
{
TargetEntry *tle = (TargetEntry *) lfirst(lc);
- /* The equal() check should be redundant, but let's be paranoid */
+ /*
+ * Usually the equal() check is redundant, but in setop plans it may
+ * not be, since prepunion.c assigns ressortgroupref equal to the
+ * column resno without regard to whether that matches the topmost
+ * level's sortgrouprefs and without regard to whether any implicit
+ * coercions are added in the setop tree. We might have to clean that
+ * up someday; but for now, just ignore any false matches.
+ */
if (tle->ressortgroupref == sortgroupref &&
equal(node, tle->expr))
{