Include the backend ID in the relpath of temporary relations.

This allows us to reliably remove all leftover temporary relation
files on cluster startup without reference to system catalogs or WAL;
therefore, we no longer include temporary relations in XLOG_XACT_COMMIT
and XLOG_XACT_ABORT WAL records.

Since these changes require including a backend ID in each
SharedInvalSmgrMsg, the size of the SharedInvalidationMessage.id
field has been reduced from two bytes to one, and the maximum number
of connections has been reduced from INT_MAX / 4 to 2^23-1.  It would
be possible to remove these restrictions by increasing the size of
SharedInvalidationMessage by 4 bytes, but right now that doesn't seem
like a good trade-off.

Review by Jaime Casanova and Tom Lane.

3 files changed, 9 insertions, 9 deletions

diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c
index 681a7aaa92d..19e1b7251e5 100644
--- a/src/backend/commands/copy.c
+++ b/src/backend/commands/copy.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/copy.c,v 1.328 2010/07/22 00:47:52 rhaas Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/copy.c,v 1.329 2010/08/13 20:10:50 rhaas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1019,7 +1019,7 @@ DoCopy(const CopyStmt *stmt, const char *queryString)
 		ExecCheckRTPerms(list_make1(rte), true);
 
 		/* check read-only transaction */
-		if (XactReadOnly && is_from && !cstate->rel->rd_islocaltemp)
+		if (XactReadOnly && is_from && cstate->rel->rd_backend != MyBackendId)
 			PreventCommandIfReadOnly("COPY FROM");
 
 		/* Don't allow COPY w/ OIDs to or from a table without them */
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index 0f06bba8039..6e0930f8d02 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/sequence.c,v 1.169 2010/07/25 23:21:21 rhaas Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/sequence.c,v 1.170 2010/08/13 20:10:51 rhaas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -472,7 +472,7 @@ nextval_internal(Oid relid)
 						RelationGetRelationName(seqrel))));
 
 	/* read-only transactions may only modify temp sequences */
-	if (!seqrel->rd_islocaltemp)
+	if (seqrel->rd_backend != MyBackendId)
 		PreventCommandIfReadOnly("nextval()");
 
 	if (elm->last != elm->cached)		/* some numbers were cached */
@@ -749,7 +749,7 @@ do_setval(Oid relid, int64 next, bool iscalled)
 						RelationGetRelationName(seqrel))));
 
 	/* read-only transactions may only modify temp sequences */
-	if (!seqrel->rd_islocaltemp)
+	if (seqrel->rd_backend != MyBackendId)
 		PreventCommandIfReadOnly("setval()");
 
 	/* lock page' buffer and read tuple */
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 221e6417eb3..703fd7e71b2 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.339 2010/08/05 14:45:01 rhaas Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.340 2010/08/13 20:10:51 rhaas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -7165,13 +7165,13 @@ ATExecSetTableSpace(Oid tableOid, Oid newTableSpace, LOCKMODE lockmode)
 	 * Relfilenodes are not unique across tablespaces, so we need to allocate
 	 * a new one in the new tablespace.
 	 */
-	newrelfilenode = GetNewRelFileNode(newTableSpace, NULL);
+	newrelfilenode = GetNewRelFileNode(newTableSpace, NULL, rel->rd_backend);
 
 	/* Open old and new relation */
 	newrnode = rel->rd_node;
 	newrnode.relNode = newrelfilenode;
 	newrnode.spcNode = newTableSpace;
-	dstrel = smgropen(newrnode);
+	dstrel = smgropen(newrnode, rel->rd_backend);
 
 	RelationOpenSmgr(rel);
 
@@ -7262,7 +7262,7 @@ copy_relation_data(SMgrRelation src, SMgrRelation dst,
 
 		/* XLOG stuff */
 		if (use_wal)
-			log_newpage(&dst->smgr_rnode, forkNum, blkno, page);
+			log_newpage(&dst->smgr_rnode.node, forkNum, blkno, page);
 
 		/*
 		 * Now write the page.	We say isTemp = true even if it's not a temp