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, 12 insertions, 8 deletions

diff --git a/src/backend/executor/nodeMergejoin.c b/src/backend/executor/nodeMergejoin.c
index 9d4ca0a8d54..dbeaa7a2a53 100644
--- a/src/backend/executor/nodeMergejoin.c
+++ b/src/backend/executor/nodeMergejoin.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/executor/nodeMergejoin.c,v 1.38 2000/09/12 21:06:48 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/executor/nodeMergejoin.c,v 1.39 2000/11/16 22:30:22 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -147,26 +147,29 @@ MJFormSkipQual(List *qualList, char *replaceopname)
 		 *	 if we search with the actual operand types.
 		 * ----------------
 		 */
-		optup = get_operator_tuple(op->opno);
+		optup = SearchSysCache(OPEROID,
+							   ObjectIdGetDatum(op->opno),
+							   0, 0, 0);
 		if (!HeapTupleIsValid(optup))	/* shouldn't happen */
 			elog(ERROR, "MJFormSkipQual: operator %u not found", op->opno);
 		opform = (Form_pg_operator) GETSTRUCT(optup);
 		oprleft = opform->oprleft;
 		oprright = opform->oprright;
+		ReleaseSysCache(optup);
 
 		/* ----------------
 		 *	 Now look up the matching "<" or ">" operator.	If there isn't one,
 		 *	 whoever marked the "=" operator mergejoinable was a loser.
 		 * ----------------
 		 */
-		optup = SearchSysCacheTuple(OPERNAME,
-									PointerGetDatum(replaceopname),
-									ObjectIdGetDatum(oprleft),
-									ObjectIdGetDatum(oprright),
-									CharGetDatum('b'));
+		optup = SearchSysCache(OPERNAME,
+							   PointerGetDatum(replaceopname),
+							   ObjectIdGetDatum(oprleft),
+							   ObjectIdGetDatum(oprright),
+							   CharGetDatum('b'));
 		if (!HeapTupleIsValid(optup))
 			elog(ERROR,
-			"MJFormSkipQual: mergejoin operator %u has no matching %s op",
+				 "MJFormSkipQual: mergejoin operator %u has no matching %s op",
 				 op->opno, replaceopname);
 		opform = (Form_pg_operator) GETSTRUCT(optup);
 
@@ -177,6 +180,7 @@ MJFormSkipQual(List *qualList, char *replaceopname)
 		op->opno = optup->t_data->t_oid;
 		op->opid = opform->oprcode;
 		op->op_fcache = NULL;
+		ReleaseSysCache(optup);
 	}
 
 	return qualCopy;