Fix relcache to account properly for subtransaction status of 'new'

relcache entries.  Also, change TransactionIdIsCurrentTransactionId()
so that if consulted during transaction abort, it will not say that
the aborted xact is still current.  (It would be better to ensure that
it's never called at all during abort, but I'm not sure we can easily
guarantee that.)  In combination, these fix a crash we have seen
occasionally during parallel regression tests of 8.0.

1 files changed, 20 insertions, 9 deletions

diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 481cdb2465f..7f0c1351bd6 100644
--- a/src/include/utils/rel.h
+++ b/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 1.76 2004/07/17 03:31:47 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/utils/rel.h,v 1.77 2004/08/28 20:31:44 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -110,17 +110,18 @@ typedef struct RelationData
 	BlockNumber rd_targblock;	/* current insertion target block, or
 								 * InvalidBlockNumber */
 	int			rd_refcnt;		/* reference count */
-	bool		rd_isnew;		/* rel was created in current xact */
-
-	/*
-	 * NOTE: rd_isnew should be relied on only for optimization purposes;
-	 * it is possible for new-ness to be "forgotten" (eg, after CLUSTER).
-	 */
 	bool		rd_istemp;		/* rel uses the local buffer mgr */
-	char		rd_isnailed;	/* rel is nailed in cache: 0 = no, 1 = yes,
-								 * 2 = yes but possibly invalid */
+	bool		rd_isnailed;	/* rel is nailed in cache */
+	bool		rd_isvalid;		/* relcache entry is valid */
 	char		rd_indexvalid;	/* state of rd_indexlist: 0 = not valid,
 								 * 1 = valid, 2 = temporarily forced */
+	TransactionId rd_createxact; /* rel was created in current xact */
+	/*
+	 * rd_createxact is the XID of the highest subtransaction the rel has
+	 * survived into; or zero if the rel was not created in the current
+	 * transaction.  This should be relied on only for optimization purposes;
+	 * it is possible for new-ness to be "forgotten" (eg, after CLUSTER).
+	 */
 	Form_pg_class rd_rel;		/* RELATION tuple */
 	TupleDesc	rd_att;			/* tuple descriptor */
 	Oid			rd_id;			/* relation's object id */
@@ -230,6 +231,16 @@ typedef Relation *RelationPtr;
 #define RelationGetNamespace(relation) \
 	((relation)->rd_rel->relnamespace)
 
+/*
+ * RELATION_IS_LOCAL
+ *		If a rel is either temp or newly created in the current transaction,
+ *		it can be assumed to be visible only to the current backend.
+ *
+ * Beware of multiple eval of argument
+ */
+#define RELATION_IS_LOCAL(relation) \
+	((relation)->rd_istemp || TransactionIdIsValid((relation)->rd_createxact))
+
 /* routines in utils/cache/relcache.c */
 extern void RelationIncrementReferenceCount(Relation rel);
 extern void RelationDecrementReferenceCount(Relation rel);