Change SearchSysCache coding conventions so that a reference count is

maintained for each cache entry.  A cache entry will not be freed until
the matching ReleaseSysCache call has been executed.  This eliminates
worries about cache entries getting dropped while still in use.  See
my posting to pg-hackers of even date for more info.

1 files changed, 22 insertions, 26 deletions

diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c
index 5ed42accdb0..43577f94f99 100644
--- a/src/backend/optimizer/path/indxpath.c
+++ b/src/backend/optimizer/path/indxpath.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/path/indxpath.c,v 1.97 2000/09/29 18:21:32 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/path/indxpath.c,v 1.98 2000/11/16 22:30:24 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -808,9 +808,9 @@ indexable_operator(Expr *clause, Oid opclass, Oid relam,
 				   bool indexkey_on_left)
 {
 	Oid			expr_op = ((Oper *) clause->oper)->opno;
-	Oid			commuted_op;
-	Operator	oldop,
-				newop;
+	Oid			commuted_op,
+				new_op;
+	Operator	oldoptup;
 	Form_pg_operator oldopform;
 	char	   *opname;
 	Oid			ltype,
@@ -835,13 +835,16 @@ indexable_operator(Expr *clause, Oid opclass, Oid relam,
 	 * Get the nominal input types of the given operator and the actual
 	 * type (before binary-compatible relabeling) of the index key.
 	 */
-	oldop = get_operator_tuple(expr_op);
-	if (! HeapTupleIsValid(oldop))
+	oldoptup = SearchSysCache(OPEROID,
+							  ObjectIdGetDatum(expr_op),
+							  0, 0, 0);
+	if (! HeapTupleIsValid(oldoptup))
 		return InvalidOid;		/* probably can't happen */
-	oldopform = (Form_pg_operator) GETSTRUCT(oldop);
-	opname = NameStr(oldopform->oprname);
+	oldopform = (Form_pg_operator) GETSTRUCT(oldoptup);
+	opname = pstrdup(NameStr(oldopform->oprname));
 	ltype = oldopform->oprleft;
 	rtype = oldopform->oprright;
+	ReleaseSysCache(oldoptup);
 
 	if (indexkey_on_left)
 	{
@@ -875,13 +878,11 @@ indexable_operator(Expr *clause, Oid opclass, Oid relam,
 	 * (In theory this might find a non-semantically-comparable operator,
 	 * but in practice that seems pretty unlikely for binary-compatible types.)
 	 */
-	newop = oper(opname, indexkeytype, indexkeytype, TRUE);
+	new_op = oper_oid(opname, indexkeytype, indexkeytype, true);
 
-	if (HeapTupleIsValid(newop))
+	if (OidIsValid(new_op))
 	{
-		Oid			new_expr_op = oprid(newop);
-
-		if (new_expr_op != expr_op)
+		if (new_op != expr_op)
 		{
 
 			/*
@@ -889,14 +890,14 @@ indexable_operator(Expr *clause, Oid opclass, Oid relam,
 			 * name; now does it match the index?
 			 */
 			if (indexkey_on_left)
-				commuted_op = new_expr_op;
+				commuted_op = new_op;
 			else
-				commuted_op = get_commutator(new_expr_op);
+				commuted_op = get_commutator(new_op);
 			if (commuted_op == InvalidOid)
 				return InvalidOid;
 
 			if (op_class(commuted_op, opclass, relam))
-				return new_expr_op;
+				return new_op;
 		}
 	}
 
@@ -2079,16 +2080,11 @@ prefix_quals(Var *leftop, Oid expr_op,
 static Oid
 find_operator(const char *opname, Oid datatype)
 {
-	HeapTuple	optup;
-
-	optup = SearchSysCacheTuple(OPERNAME,
-								PointerGetDatum(opname),
-								ObjectIdGetDatum(datatype),
-								ObjectIdGetDatum(datatype),
-								CharGetDatum('b'));
-	if (!HeapTupleIsValid(optup))
-		return InvalidOid;
-	return optup->t_data->t_oid;
+	return GetSysCacheOid(OPERNAME,
+						  PointerGetDatum(opname),
+						  ObjectIdGetDatum(datatype),
+						  ObjectIdGetDatum(datatype),
+						  CharGetDatum('b'));
 }
 
 /*