*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/optimizer/plan/setrefs.c,v 1.154 2009/10/26 02:26:34 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/optimizer/plan/setrefs.c,v 1.155 2009/11/16 18:04:40 tgl Exp $
*
*-------------------------------------------------------------------------
*/
static Var *search_indexed_tlist_for_non_var(Node *node,
indexed_tlist *itlist,
Index newvarno);
+static Var *search_indexed_tlist_for_sortgroupref(Node *node,
+ Index sortgroupref,
+ indexed_tlist *itlist,
+ Index newvarno);
static List *fix_join_expr(PlannerGlobal *glob,
List *clauses,
indexed_tlist *outer_itlist,
TargetEntry *tle = (TargetEntry *) lfirst(l);
Node *newexpr;
- newexpr = fix_upper_expr(glob,
- (Node *) tle->expr,
- subplan_itlist,
- rtoffset);
+ /* If it's a non-Var sort/group item, first try to match by sortref */
+ if (tle->ressortgroupref != 0 && !IsA(tle->expr, Var))
+ {
+ newexpr = (Node *)
+ search_indexed_tlist_for_sortgroupref((Node *) tle->expr,
+ tle->ressortgroupref,
+ subplan_itlist,
+ OUTER);
+ if (!newexpr)
+ newexpr = fix_upper_expr(glob,
+ (Node *) tle->expr,
+ subplan_itlist,
+ rtoffset);
+ }
+ else
+ newexpr = fix_upper_expr(glob,
+ (Node *) tle->expr,
+ subplan_itlist,
+ rtoffset);
tle = flatCopyTargetEntry(tle);
tle->expr = (Expr *) newexpr;
output_targetlist = lappend(output_targetlist, tle);
return NULL; /* no match */
}
+/*
+ * 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 */
+}
+
/*
* fix_join_expr
* Create a new set of targetlist entries or join qual clauses by