Clean up optimizer's handling of indexscan quals that need to be

commuted (ie, the index var appears on the right).  These are now handled
the same way as merge and hash join quals that need to be commuted: the
actual reversing of the clause only happens if we actually choose the path
and generate a plan from it.  Furthermore, the clause is only reversed in
the 'indexqual' field of the plan, not in the 'indxqualorig' field.  This
allows the clause to still be recognized and removed from qpquals of upper
level join plans.  Also, simplify and generalize match_clause_to_indexkey;
now it recognizes binary-compatible indexes for join as well as restriction
clauses.

1 files changed, 15 insertions, 14 deletions

diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c
index 322aeba1ce3..f9906cffc04 100644
--- a/src/backend/optimizer/util/clauses.c
+++ b/src/backend/optimizer/util/clauses.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/util/clauses.c,v 1.45 1999/08/10 03:00:15 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/util/clauses.c,v 1.46 1999/08/12 04:32:54 tgl Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -666,38 +666,39 @@ get_rels_atts(Node *clause,
  *--------------------
  */
 void
-CommuteClause(Node *clause)
+CommuteClause(Expr *clause)
 {
-	Node	   *temp;
-	Oper	   *commu;
-	Form_pg_operator commuTup;
 	HeapTuple	heapTup;
+	Form_pg_operator commuTup;
+	Oper	   *commu;
+	Node	   *temp;
 
-	if (!is_opclause(clause))
-		elog(ERROR, "CommuteClause: applied to non-operator clause");
+	if (!is_opclause((Node *) clause) ||
+		length(clause->args) != 2)
+		elog(ERROR, "CommuteClause: applied to non-binary-operator clause");
 
 	heapTup = (HeapTuple)
-		get_operator_tuple(get_commutator(((Oper *) ((Expr *) clause)->oper)->opno));
+		get_operator_tuple(get_commutator(((Oper *) clause->oper)->opno));
 
 	if (heapTup == (HeapTuple) NULL)
 		elog(ERROR, "CommuteClause: no commutator for operator %u",
-			 ((Oper *) ((Expr *) clause)->oper)->opno);
+			 ((Oper *) clause->oper)->opno);
 
 	commuTup = (Form_pg_operator) GETSTRUCT(heapTup);
 
 	commu = makeOper(heapTup->t_data->t_oid,
 					 commuTup->oprcode,
 					 commuTup->oprresult,
-					 ((Oper *) ((Expr *) clause)->oper)->opsize,
+					 ((Oper *) clause->oper)->opsize,
 					 NULL);
 
 	/*
 	 * re-form the clause in-place!
 	 */
-	((Expr *) clause)->oper = (Node *) commu;
-	temp = lfirst(((Expr *) clause)->args);
-	lfirst(((Expr *) clause)->args) = lsecond(((Expr *) clause)->args);
-	lsecond(((Expr *) clause)->args) = temp;
+	clause->oper = (Node *) commu;
+	temp = lfirst(clause->args);
+	lfirst(clause->args) = lsecond(clause->args);
+	lsecond(clause->args) = temp;
 }