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, 5 deletions

diff --git a/src/include/utils/syscache.h b/src/include/utils/syscache.h
index 5d17e8db44c..73abd53e134 100644
--- a/src/include/utils/syscache.h
+++ b/src/include/utils/syscache.h
@@ -9,7 +9,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: syscache.h,v 1.26 2000/06/17 04:56:29 tgl Exp $
+ * $Id: syscache.h,v 1.27 2000/11/16 22:30:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -57,12 +57,22 @@
 #define TYPENAME		26
 #define TYPEOID			27
 
-extern void zerocaches(void);
 extern void InitCatalogCache(void);
-extern HeapTuple SearchSysCacheTuple(int cacheId,
+
+extern HeapTuple SearchSysCache(int cacheId,
+					Datum key1, Datum key2, Datum key3, Datum key4);
+extern void ReleaseSysCache(HeapTuple tuple);
+
+/* convenience routines */
+extern HeapTuple SearchSysCacheCopy(int cacheId,
 					Datum key1, Datum key2, Datum key3, Datum key4);
-extern HeapTuple SearchSysCacheTupleCopy(int cacheId,
-						Datum key1, Datum key2, Datum key3, Datum key4);
+extern Oid GetSysCacheOid(int cacheId,
+					Datum key1, Datum key2, Datum key3, Datum key4);
+
+/* macro for just probing for existence of a tuple via the syscache */
+#define SearchSysCacheExists(c,k1,k2,k3,k4)  \
+	OidIsValid(GetSysCacheOid(c,k1,k2,k3,k4))
+
 extern Datum SysCacheGetAttr(int cacheId, HeapTuple tup,
 				AttrNumber attributeNumber, bool *isNull);