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.

1 files changed, 10 insertions, 11 deletions

diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 0491d2c8d91..6015eaab1db 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.297 2010/08/13 15:42:21 rhaas Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.298 2010/08/13 20:10:50 rhaas Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -912,7 +912,6 @@ RecordTransactionCommit(void)
 	TransactionId latestXid = InvalidTransactionId;
 	int			nrels;
 	RelFileNode *rels;
-	bool		haveNonTemp;
 	int			nchildren;
 	TransactionId *children;
 	int			nmsgs = 0;
@@ -920,7 +919,7 @@ RecordTransactionCommit(void)
 	bool		RelcacheInitFileInval = false;
 
 	/* Get data needed for commit record */
-	nrels = smgrGetPendingDeletes(true, &rels, &haveNonTemp);
+	nrels = smgrGetPendingDeletes(true, &rels);
 	nchildren = xactGetCommittedChildren(&children);
 	if (XLogStandbyInfoActive())
 		nmsgs = xactGetCommittedInvalidationMessages(&invalMessages,
@@ -1048,7 +1047,7 @@ RecordTransactionCommit(void)
 	 * asynchronous commit if all to-be-deleted tables are temporary though,
 	 * since they are lost anyway if we crash.)
 	 */
-	if (XactSyncCommit || forceSyncCommit || haveNonTemp)
+	if (XactSyncCommit || forceSyncCommit || nrels > 0)
 	{
 		/*
 		 * Synchronous commit case:
@@ -1334,7 +1333,7 @@ RecordTransactionAbort(bool isSubXact)
 			 xid);
 
 	/* Fetch the data we need for the abort record */
-	nrels = smgrGetPendingDeletes(false, &rels, NULL);
+	nrels = smgrGetPendingDeletes(false, &rels);
 	nchildren = xactGetCommittedChildren(&children);
 
 	/* XXX do we really need a critical section here? */
@@ -4474,7 +4473,7 @@ xact_redo_commit(xl_xact_commit *xlrec, TransactionId xid, XLogRecPtr lsn)
 	/* Make sure files supposed to be dropped are dropped */
 	for (i = 0; i < xlrec->nrels; i++)
 	{
-		SMgrRelation srel = smgropen(xlrec->xnodes[i]);
+		SMgrRelation srel = smgropen(xlrec->xnodes[i], InvalidBackendId);
 		ForkNumber	fork;
 
 		for (fork = 0; fork <= MAX_FORKNUM; fork++)
@@ -4482,7 +4481,7 @@ xact_redo_commit(xl_xact_commit *xlrec, TransactionId xid, XLogRecPtr lsn)
 			if (smgrexists(srel, fork))
 			{
 				XLogDropRelation(xlrec->xnodes[i], fork);
-				smgrdounlink(srel, fork, false, true);
+				smgrdounlink(srel, fork, true);
 			}
 		}
 		smgrclose(srel);
@@ -4579,7 +4578,7 @@ xact_redo_abort(xl_xact_abort *xlrec, TransactionId xid)
 	/* Make sure files supposed to be dropped are dropped */
 	for (i = 0; i < xlrec->nrels; i++)
 	{
-		SMgrRelation srel = smgropen(xlrec->xnodes[i]);
+		SMgrRelation srel = smgropen(xlrec->xnodes[i], InvalidBackendId);
 		ForkNumber	fork;
 
 		for (fork = 0; fork <= MAX_FORKNUM; fork++)
@@ -4587,7 +4586,7 @@ xact_redo_abort(xl_xact_abort *xlrec, TransactionId xid)
 			if (smgrexists(srel, fork))
 			{
 				XLogDropRelation(xlrec->xnodes[i], fork);
-				smgrdounlink(srel, fork, false, true);
+				smgrdounlink(srel, fork, true);
 			}
 		}
 		smgrclose(srel);
@@ -4661,7 +4660,7 @@ xact_desc_commit(StringInfo buf, xl_xact_commit *xlrec)
 		appendStringInfo(buf, "; rels:");
 		for (i = 0; i < xlrec->nrels; i++)
 		{
-			char	   *path = relpath(xlrec->xnodes[i], MAIN_FORKNUM);
+			char	   *path = relpathperm(xlrec->xnodes[i], MAIN_FORKNUM);
 
 			appendStringInfo(buf, " %s", path);
 			pfree(path);
@@ -4716,7 +4715,7 @@ xact_desc_abort(StringInfo buf, xl_xact_abort *xlrec)
 		appendStringInfo(buf, "; rels:");
 		for (i = 0; i < xlrec->nrels; i++)
 		{
-			char	   *path = relpath(xlrec->xnodes[i], MAIN_FORKNUM);
+			char	   *path = relpathperm(xlrec->xnodes[i], MAIN_FORKNUM);
 
 			appendStringInfo(buf, " %s", path);
 			pfree(path);