Make OIDs optional, per discussions in pghackers. WITH OIDS is still the

default, but OIDS are removed from many system catalogs that don't need them.
Some interesting side effects: TOAST pointers are 20 bytes not 32 now;
pg_description has a three-column key instead of one.

Bugs fixed in passing: BINARY cursors work again; pg_class.relhaspkey
has some usefulness; pg_dump dumps comments on indexes, rules, and
triggers in a valid order.

initdb forced.

src/backend/utils/cache/syscache.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/syscache.c,v 1.63 2001/06/18 03:35:07 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/cache/syscache.c,v 1.64 2001/08/10 18:57:37 tgl Exp $
  *
  * NOTES
  *	  These routines allow the parser/planner/executor to perform
@@ -485,6 +485,28 @@ SearchSysCacheCopy(int cacheId,
 	return newtuple;
 }
 
+/*
+ * SearchSysCacheExists
+ *
+ * A convenience routine that just probes to see if a tuple can be found.
+ * No lock is retained on the syscache entry.
+ */
+bool
+SearchSysCacheExists(int cacheId,
+					 Datum key1,
+					 Datum key2,
+					 Datum key3,
+					 Datum key4)
+{
+	HeapTuple	tuple;
+
+	tuple = SearchSysCache(cacheId, key1, key2, key3, key4);
+	if (!HeapTupleIsValid(tuple))
+		return false;
+	ReleaseSysCache(tuple);
+	return true;
+}
+
 /*
  * GetSysCacheOid
  *