Last week's patch for make_sort_from_pathkeys wasn't good enough: it has

to be able to discard top-level RelabelType nodes on *both* sides of the
equivalence-class-to-target-list comparison, since make_pathkey_from_sortinfo
might either add or remove a RelabelType.  Also fix the latter to do the
removal case cleanly.  Per example from Peter.

1 files changed, 29 insertions, 1 deletions

diff --git a/src/backend/optimizer/util/tlist.c b/src/backend/optimizer/util/tlist.c
index 1e507235c53..e58fe7dc7f1 100644
--- a/src/backend/optimizer/util/tlist.c
+++ b/src/backend/optimizer/util/tlist.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/util/tlist.c,v 1.74 2007/01/05 22:19:33 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/util/tlist.c,v 1.75 2007/11/08 19:25:37 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -45,6 +45,34 @@ tlist_member(Node *node, List *targetlist)
 }
 
 /*
+ * tlist_member_ignore_relabel
+ *	  Same as above, except that we ignore top-level RelabelType nodes
+ *	  while checking for a match.  This is needed for some scenarios
+ *	  involving binary-compatible sort operations.
+ */
+TargetEntry *
+tlist_member_ignore_relabel(Node *node, List *targetlist)
+{
+	ListCell   *temp;
+
+	while (node && IsA(node, RelabelType))
+		node = (Node *) ((RelabelType *) node)->arg;
+
+	foreach(temp, targetlist)
+	{
+		TargetEntry *tlentry = (TargetEntry *) lfirst(temp);
+		Expr   *tlexpr = tlentry->expr;
+
+		while (tlexpr && IsA(tlexpr, RelabelType))
+			tlexpr = ((RelabelType *) tlexpr)->arg;
+
+		if (equal(node, tlexpr))
+			return tlentry;
+	}
+	return NULL;
+}
+
+/*
  * flatten_tlist
  *	  Create a target list that only contains unique variables.
  *