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.

src/backend/commands/define.c

@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/define.c,v 1.47 2000/10/07 00:58:16 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/define.c,v 1.48 2000/11/16 22:30:18 tgl Exp $
  *
  * DESCRIPTION
  *	  The "DefineFoo" routines take the parse tree and pick out the
@@ -277,10 +277,9 @@ CreateFunction(ProcedureStmt *stmt, CommandDest dest)
 		Form_pg_language languageStruct;
 
 		/* Lookup the language in the system cache */
-		languageTuple = SearchSysCacheTuple(LANGNAME,
-											PointerGetDatum(languageName),
-											0, 0, 0);
-
+		languageTuple = SearchSysCache(LANGNAME,
+									   PointerGetDatum(languageName),
+									   0, 0, 0);
 		if (!HeapTupleIsValid(languageTuple))
 			elog(ERROR,
 				 "Unrecognized language specified in a CREATE FUNCTION: "
@@ -299,12 +298,12 @@ CreateFunction(ProcedureStmt *stmt, CommandDest dest)
 		 * be defined by postgres superusers only
 		 */
 		if (!languageStruct->lanpltrusted && !superuser())
-		{
 			elog(ERROR, "Only users with Postgres superuser privilege "
 				 "are permitted to create a function in the '%s' "
 				 "language.",
 				 languageName);
-		}
+
+		ReleaseSysCache(languageTuple);
 	}
 
 	/*