+/*
+ * search_indexed_tlist_for_sortgroupref --- find a sort/group expression
+ * (which is assumed not to be just a Var)
+ *
+ * If a match is found, return a Var constructed to reference the tlist item.
+ * If no match, return NULL.
+ *
+ * This is needed to ensure that we select the right subplan TLE in cases
+ * where there are multiple textually-equal()-but-volatile sort expressions.
+ * And it's also faster than search_indexed_tlist_for_non_var.
+ */
+static Var *
+search_indexed_tlist_for_sortgroupref(Node *node,
+ Index sortgroupref,
+ indexed_tlist *itlist,
+ Index newvarno)
+{
+ ListCell *lc;
+
+ foreach(lc, itlist->tlist)
+ {
+ TargetEntry *tle = (TargetEntry *) lfirst(lc);
+
+ /* The equal() check should be redundant, but let's be paranoid */
+ if (tle->ressortgroupref == sortgroupref &&
+ equal(node, tle->expr))
+ {
+ /* Found a matching subplan output expression */
+ Var *newvar;
+
+ newvar = makeVar(newvarno,
+ tle->resno,
+ exprType((Node *) tle->expr),
+ exprTypmod((Node *) tle->expr),
+ 0);
+ newvar->varnoold = 0; /* wasn't ever a plain Var */
+ newvar->varoattno = 0;
+ return newvar;
+ }
+ }
+ return NULL; /* no match */
+}
+