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, 15 insertions, 21 deletions

diff --git a/src/backend/access/common/printtup.c b/src/backend/access/common/printtup.c
index 6fe0e9652c2..ccf3071b502 100644
--- a/src/backend/access/common/printtup.c
+++ b/src/backend/access/common/printtup.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/common/printtup.c,v 1.53 2000/05/30 04:24:27 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/common/printtup.c,v 1.54 2000/11/16 22:30:15 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -36,7 +36,7 @@ static void printtup_cleanup(DestReceiver *self);
  *		getTypeOutAndElem -- get both typoutput and typelem for a type
  *
  * We used to fetch these with two separate function calls,
- * typtoout() and gettypelem(), which each called SearchSysCacheTuple.
+ * typtoout() and gettypelem(), which each called SearchSysCache.
  * This way takes half the time.
  * ----------------
  */
@@ -44,25 +44,19 @@ int
 getTypeOutAndElem(Oid type, Oid *typOutput, Oid *typElem)
 {
 	HeapTuple	typeTuple;
-
-	typeTuple = SearchSysCacheTuple(TYPEOID,
-									ObjectIdGetDatum(type),
-									0, 0, 0);
-
-	if (HeapTupleIsValid(typeTuple))
-	{
-		Form_pg_type pt = (Form_pg_type) GETSTRUCT(typeTuple);
-
-		*typOutput = (Oid) pt->typoutput;
-		*typElem = (Oid) pt->typelem;
-		return OidIsValid(*typOutput);
-	}
-
-	elog(ERROR, "getTypeOutAndElem: Cache lookup of type %u failed", type);
-
-	*typOutput = InvalidOid;
-	*typElem = InvalidOid;
-	return 0;
+	Form_pg_type pt;
+
+	typeTuple = SearchSysCache(TYPEOID,
+							   ObjectIdGetDatum(type),
+							   0, 0, 0);
+	if (!HeapTupleIsValid(typeTuple))
+		elog(ERROR, "getTypeOutAndElem: Cache lookup of type %u failed", type);
+	pt = (Form_pg_type) GETSTRUCT(typeTuple);
+
+	*typOutput = pt->typoutput;
+	*typElem = pt->typelem;
+	ReleaseSysCache(typeTuple);
+	return OidIsValid(*typOutput);
 }
 
 /* ----------------