Invent ResourceOwner mechanism as per my recent proposal, and use it to

keep track of portal-related resources separately from transaction-related
resources.  This allows cursors to work in a somewhat sane fashion with
nested transactions.  For now, cursor behavior is non-subtransactional,
that is a cursor's state does not roll back if you abort a subtransaction
that fetched from the cursor.  We might want to change that later.

src/include/utils/rel.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/rel.h,v 1.75 2004/07/01 00:51:44 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/utils/rel.h,v 1.76 2004/07/17 03:31:47 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -110,9 +110,6 @@ typedef struct RelationData
 	BlockNumber rd_targblock;	/* current insertion target block, or
 								 * InvalidBlockNumber */
 	int			rd_refcnt;		/* reference count */
-	int		   *rd_prevrefcnt;	/* reference count stack */
-	int			rd_numalloc;	/* stack allocated size */
-	int			rd_numpushed;	/* stack used size */
 	bool		rd_isnew;		/* rel was created in current xact */
 
 	/*
@@ -190,28 +187,6 @@ typedef Relation *RelationPtr;
 #define RelationHasReferenceCountZero(relation) \
 		((bool)((relation)->rd_refcnt == 0))
 
-/*
- * RelationSetReferenceCount
- *		Sets relation reference count.
- */
-#define RelationSetReferenceCount(relation,count) \
-	((relation)->rd_refcnt = (count))
-
-/*
- * RelationIncrementReferenceCount
- *		Increments relation reference count.
- */
-#define RelationIncrementReferenceCount(relation) \
-	((relation)->rd_refcnt += 1)
-
-/*
- * RelationDecrementReferenceCount
- *		Decrements relation reference count.
- */
-#define RelationDecrementReferenceCount(relation) \
-	(AssertMacro((relation)->rd_refcnt > 0), \
-	 (relation)->rd_refcnt -= 1)
-
 /*
  * RelationGetForm
  *		Returns pg_class tuple for a relation.
@@ -255,4 +230,8 @@ typedef Relation *RelationPtr;
 #define RelationGetNamespace(relation) \
 	((relation)->rd_rel->relnamespace)
 
+/* routines in utils/cache/relcache.c */
+extern void RelationIncrementReferenceCount(Relation rel);
+extern void RelationDecrementReferenceCount(Relation rel);
+
 #endif   /* REL_H */