including backend ID in relpath of temp rels - updated patch

diff --git a/src/backend/access/heap/visibilitymap.c b/src/backend/access/heap/visibilitymap.c
index d1f7bcc..9645c95 100644
--- a/src/backend/access/heap/visibilitymap.c
+++ b/src/backend/access/heap/visibilitymap.c
@@ -373,8 +373,7 @@ visibilitymap_truncate(Relation rel, BlockNumber nheapblocks)
 	}
 
 	/* Truncate the unused VM pages, and send smgr inval message */
-	smgrtruncate(rel->rd_smgr, VISIBILITYMAP_FORKNUM, newnblocks,
-				 rel->rd_istemp);
+	smgrtruncate(rel->rd_smgr, VISIBILITYMAP_FORKNUM, newnblocks);
 
 	/*
 	 * We might as well update the local smgr_vm_nblocks setting. smgrtruncate
diff --git a/src/backend/access/nbtree/nbtsort.c b/src/backend/access/nbtree/nbtsort.c
index 89ed8a0..06e304e 100644
--- a/src/backend/access/nbtree/nbtsort.c
+++ b/src/backend/access/nbtree/nbtsort.c
@@ -295,9 +295,8 @@ _bt_blwritepage(BTWriteState *wstate, Page page, BlockNumber blkno)
 	}
 
 	/*
-	 * Now write the page.	We say isTemp = true even if it's not a temp
-	 * index, because there's no need for smgr to schedule an fsync for this
-	 * write; we'll do it ourselves before ending the build.
+	 * Now write the page.	There's no need for smgr to schedule an fsync for
+	 * this write; we'll do it ourselves before ending the build.
 	 */
 	if (blkno == wstate->btws_pages_written)
 	{
diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c
index d0680f0..615a7fa 100644
--- a/src/backend/access/transam/twophase.c
+++ b/src/backend/access/transam/twophase.c
@@ -865,8 +865,8 @@ StartPrepare(GlobalTransaction gxact)
 	hdr.prepared_at = gxact->prepared_at;
 	hdr.owner = gxact->owner;
 	hdr.nsubxacts = xactGetCommittedChildren(&children);
-	hdr.ncommitrels = smgrGetPendingDeletes(true, &commitrels, NULL);
-	hdr.nabortrels = smgrGetPendingDeletes(false, &abortrels, NULL);
+	hdr.ncommitrels = smgrGetPendingDeletes(true, &commitrels);
+	hdr.nabortrels = smgrGetPendingDeletes(false, &abortrels);
 	hdr.ninvalmsgs = xactGetCommittedInvalidationMessages(&invalmsgs,
 														  &hdr.initfileinval);
 	StrNCpy(hdr.gid, gxact->gid, GIDSIZE);
@@ -1320,13 +1320,13 @@ FinishPreparedTransaction(const char *gid, bool isCommit)
 	}
 	for (i = 0; i < ndelrels; i++)
 	{
-		SMgrRelation srel = smgropen(delrels[i]);
+		SMgrRelation srel = smgropen(delrels[i], InvalidBackendId);
 		ForkNumber	fork;
 
 		for (fork = 0; fork <= MAX_FORKNUM; fork++)
 		{
 			if (smgrexists(srel, fork))
-				smgrdounlink(srel, fork, false, false);
+				smgrdounlink(srel, fork, false);
 		}
 		smgrclose(srel);
 	}
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 6ba6534..d69e8db 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -890,7 +890,6 @@ RecordTransactionCommit(void)
 	TransactionId latestXid = InvalidTransactionId;
 	int			nrels;
 	RelFileNode *rels;
-	bool		haveNonTemp;
 	int			nchildren;
 	TransactionId *children;
 	int			nmsgs;
@@ -898,7 +897,7 @@ RecordTransactionCommit(void)
 	bool		RelcacheInitFileInval;
 
 	/* Get data needed for commit record */
-	nrels = smgrGetPendingDeletes(true, &rels, &haveNonTemp);
+	nrels = smgrGetPendingDeletes(true, &rels);
 	nchildren = xactGetCommittedChildren(&children);
 	nmsgs = xactGetCommittedInvalidationMessages(&invalMessages,
 												 &RelcacheInitFileInval);
@@ -1025,7 +1024,7 @@ 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:
@@ -1311,7 +1310,7 @@ 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? */
@@ -4451,7 +4450,7 @@ 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++)
@@ -4459,7 +4458,7 @@ 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);
@@ -4556,7 +4555,7 @@ 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++)
@@ -4564,7 +4563,7 @@ 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);
@@ -4638,7 +4637,7 @@ 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);
@@ -4693,7 +4692,7 @@ 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);
diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c
index b5bbc5e..dba842c 100644
--- a/src/backend/access/transam/xlogutils.c
+++ b/src/backend/access/transam/xlogutils.c
@@ -68,7 +68,7 @@ log_invalid_page(RelFileNode node, ForkNumber forkno, BlockNumber blkno,
 	 */
 	if (log_min_messages <= DEBUG1 || client_min_messages <= DEBUG1)
 	{
-		char	   *path = relpath(node, forkno);
+		char	   *path = relpathperm(node, forkno);
 
 		if (present)
 			elog(DEBUG1, "page %u of relation %s is uninitialized",
@@ -133,7 +133,7 @@ forget_invalid_pages(RelFileNode node, ForkNumber forkno, BlockNumber minblkno)
 		{
 			if (log_min_messages <= DEBUG2 || client_min_messages <= DEBUG2)
 			{
-				char	   *path = relpath(hentry->key.node, forkno);
+				char	   *path = relpathperm(hentry->key.node, forkno);
 
 				elog(DEBUG2, "page %u of relation %s has been dropped",
 					 hentry->key.blkno, path);
@@ -166,7 +166,7 @@ forget_invalid_pages_db(Oid dbid)
 		{
 			if (log_min_messages <= DEBUG2 || client_min_messages <= DEBUG2)
 			{
-				char	   *path = relpath(hentry->key.node, hentry->key.forkno);
+				char	   *path = relpathperm(hentry->key.node, hentry->key.forkno);
 
 				elog(DEBUG2, "page %u of relation %s has been dropped",
 					 hentry->key.blkno, path);
@@ -200,7 +200,7 @@ XLogCheckInvalidPages(void)
 	 */
 	while ((hentry = (xl_invalid_page *) hash_seq_search(&status)) != NULL)
 	{
-		char	   *path = relpath(hentry->key.node, hentry->key.forkno);
+		char	   *path = relpathperm(hentry->key.node, hentry->key.forkno);
 
 		if (hentry->present)
 			elog(WARNING, "page %u of relation %s was uninitialized",
@@ -276,7 +276,7 @@ XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
 	Assert(blkno != P_NEW);
 
 	/* Open the relation at smgr level */
-	smgr = smgropen(rnode);
+	smgr = smgropen(rnode, InvalidBackendId);
 
 	/*
 	 * Create the target file if it doesn't already exist.  This lets us cope
@@ -293,7 +293,7 @@ XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
 	if (blkno < lastblock)
 	{
 		/* page exists in file */
-		buffer = ReadBufferWithoutRelcache(rnode, false, forknum, blkno,
+		buffer = ReadBufferWithoutRelcache(rnode, forknum, blkno,
 										   mode, NULL);
 	}
 	else
@@ -312,7 +312,7 @@ XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
 		{
 			if (buffer != InvalidBuffer)
 				ReleaseBuffer(buffer);
-			buffer = ReadBufferWithoutRelcache(rnode, false, forknum,
+			buffer = ReadBufferWithoutRelcache(rnode, forknum,
 											   P_NEW, mode, NULL);
 			lastblock++;
 		}
diff --git a/src/backend/catalog/catalog.c b/src/backend/catalog/catalog.c
index 3edfc23..5ec5602 100644
--- a/src/backend/catalog/catalog.c
+++ b/src/backend/catalog/catalog.c
@@ -78,12 +78,37 @@ forkname_to_number(char *forkName)
 }
 
 /*
- * relpath			- construct path to a relation's file
+ * forkname_chars
+ * 		We use this to figure out whether a filename could be a relation
+ * 		fork (as opposed to an oddly named stray file that somehow ended
+ * 		up in the database directory).  If the passed string begins with
+ * 		a fork name (other than the main fork name), we return its length.
+ * 		If not, we return 0.
+ *
+ * Note that the present coding assumes that there are no fork names which
+ * are prefixes of other fork names.
+ */
+int
+forkname_chars(const char *str)
+{
+	ForkNumber	forkNum;
+
+	for (forkNum = 1; forkNum <= MAX_FORKNUM; forkNum++)
+	{
+		int len = strlen(forkNames[forkNum]);
+		if (strncmp(forkNames[forkNum], str, len) == 0)
+			return len;
+	}
+	return 0;
+}
+
+/*
+ * relpathbackend - construct path to a relation's file
  *
  * Result is a palloc'd string.
  */
 char *
-relpath(RelFileNode rnode, ForkNumber forknum)
+relpathbackend(RelFileNode rnode, BackendId backend, ForkNumber forknum)
 {
 	int			pathlen;
 	char	   *path;
@@ -92,6 +117,7 @@ relpath(RelFileNode rnode, ForkNumber forknum)
 	{
 		/* Shared system relations live in {datadir}/global */
 		Assert(rnode.dbNode == 0);
+		Assert(backend == InvalidBackendId);
 		pathlen = 7 + OIDCHARS + 1 + FORKNAMECHARS + 1;
 		path = (char *) palloc(pathlen);
 		if (forknum != MAIN_FORKNUM)
@@ -103,29 +129,69 @@ relpath(RelFileNode rnode, ForkNumber forknum)
 	else if (rnode.spcNode == DEFAULTTABLESPACE_OID)
 	{
 		/* The default tablespace is {datadir}/base */
-		pathlen = 5 + OIDCHARS + 1 + OIDCHARS + 1 + FORKNAMECHARS + 1;
-		path = (char *) palloc(pathlen);
-		if (forknum != MAIN_FORKNUM)
-			snprintf(path, pathlen, "base/%u/%u_%s",
-					 rnode.dbNode, rnode.relNode, forkNames[forknum]);
+		if (backend == InvalidBackendId)
+		{
+			pathlen = 5 + OIDCHARS + 1 + OIDCHARS + 1 + FORKNAMECHARS + 1;
+			path = (char *) palloc(pathlen);
+			if (forknum != MAIN_FORKNUM)
+				snprintf(path, pathlen, "base/%u/%u_%s",
+						 rnode.dbNode, rnode.relNode,
+						 forkNames[forknum]);
+			else
+				snprintf(path, pathlen, "base/%u/%u",
+						 rnode.dbNode, rnode.relNode);
+		}
 		else
-			snprintf(path, pathlen, "base/%u/%u",
-					 rnode.dbNode, rnode.relNode);
+		{
+			/* OIDCHARS will suffice for an integer, too */
+			pathlen = 5 + OIDCHARS + 2 + OIDCHARS + 1 + OIDCHARS + 1
+					+ FORKNAMECHARS + 1;
+			path = (char *) palloc(pathlen);
+			if (forknum != MAIN_FORKNUM)
+				snprintf(path, pathlen, "base/%u/t%d_%u_%s",
+						 rnode.dbNode, backend, rnode.relNode,
+						 forkNames[forknum]);
+			else
+				snprintf(path, pathlen, "base/%u/t%d_%u",
+						 rnode.dbNode, backend, rnode.relNode);
+		}
 	}
 	else
 	{
 		/* All other tablespaces are accessed via symlinks */
-		pathlen = 9 + 1 + OIDCHARS + 1 + strlen(TABLESPACE_VERSION_DIRECTORY) +
-			1 + OIDCHARS + 1 + OIDCHARS + 1 + FORKNAMECHARS + 1;
-		path = (char *) palloc(pathlen);
-		if (forknum != MAIN_FORKNUM)
-			snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/%u_%s",
-					 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
-					 rnode.dbNode, rnode.relNode, forkNames[forknum]);
+		if (backend == InvalidBackendId)
+		{
+			pathlen = 9 + 1 + OIDCHARS + 1
+					+ strlen(TABLESPACE_VERSION_DIRECTORY) + 1 + OIDCHARS + 1
+					+ OIDCHARS + 1 + FORKNAMECHARS + 1;
+			path = (char *) palloc(pathlen);
+			if (forknum != MAIN_FORKNUM)
+				snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/%u_%s",
+						 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
+						 rnode.dbNode, rnode.relNode,
+						 forkNames[forknum]);
+			else
+				snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/%u",
+						 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
+						 rnode.dbNode, rnode.relNode);
+		}
 		else
-			snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/%u",
-					 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
-					 rnode.dbNode, rnode.relNode);
+		{
+			/* OIDCHARS will suffice for an integer, too */
+			pathlen = 9 + 1 + OIDCHARS + 1
+					+ strlen(TABLESPACE_VERSION_DIRECTORY) + 1 + OIDCHARS + 2
+					+ OIDCHARS + 1 + OIDCHARS + 1 + FORKNAMECHARS + 1;
+			path = (char *) palloc(pathlen);
+			if (forknum != MAIN_FORKNUM)
+				snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/t%d_%u_%s",
+						 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
+						 rnode.dbNode, backend, rnode.relNode,
+						 forkNames[forknum]);
+			else
+				snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/t%d_%u",
+						 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
+						 rnode.dbNode, backend, rnode.relNode);
+		}
 	}
 	return path;
 }
@@ -458,16 +524,17 @@ GetNewOidWithIndex(Relation relation, Oid indexId, AttrNumber oidcolumn)
  * created by bootstrap have preassigned OIDs, so there's no need.
  */
 Oid
-GetNewRelFileNode(Oid reltablespace, Relation pg_class)
+GetNewRelFileNode(Oid reltablespace, Relation pg_class, BackendId backend)
 {
-	RelFileNode rnode;
+	BackendRelFileNode rnode;
 	char	   *rpath;
 	int			fd;
 	bool		collides;
 
 	/* This logic should match RelationInitPhysicalAddr */
-	rnode.spcNode = reltablespace ? reltablespace : MyDatabaseTableSpace;
-	rnode.dbNode = (rnode.spcNode == GLOBALTABLESPACE_OID) ? InvalidOid : MyDatabaseId;
+	rnode.node.spcNode = reltablespace ? reltablespace : MyDatabaseTableSpace;
+	rnode.node.dbNode = (rnode.node.spcNode == GLOBALTABLESPACE_OID) ? InvalidOid : MyDatabaseId;
+	rnode.backend = backend;
 
 	do
 	{
@@ -475,9 +542,9 @@ GetNewRelFileNode(Oid reltablespace, Relation pg_class)
 
 		/* Generate the OID */
 		if (pg_class)
-			rnode.relNode = GetNewOid(pg_class);
+			rnode.node.relNode = GetNewOid(pg_class);
 		else
-			rnode.relNode = GetNewObjectId();
+			rnode.node.relNode = GetNewObjectId();
 
 		/* Check for existing file of same name */
 		rpath = relpath(rnode, MAIN_FORKNUM);
@@ -508,5 +575,5 @@ GetNewRelFileNode(Oid reltablespace, Relation pg_class)
 		pfree(rpath);
 	} while (collides);
 
-	return rnode.relNode;
+	return rnode.node.relNode;
 }
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index d848ef0..6e852b4 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -39,6 +39,7 @@
 #include "catalog/heap.h"
 #include "catalog/index.h"
 #include "catalog/indexing.h"
+#include "catalog/namespace.h"
 #include "catalog/pg_attrdef.h"
 #include "catalog/pg_constraint.h"
 #include "catalog/pg_inherits.h"
@@ -975,7 +976,9 @@ heap_create_with_catalog(const char *relname,
 			binary_upgrade_next_toast_relfilenode = InvalidOid;
 		}
 		else
-			relid = GetNewRelFileNode(reltablespace, pg_class_desc);
+			relid = GetNewRelFileNode(reltablespace, pg_class_desc,
+									  isTempOrToastNamespace(relnamespace) ?
+										  MyBackendId : InvalidBackendId);
 	}
 
 	/*
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 69946fe..3408a10 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -645,7 +645,12 @@ index_create(Oid heapRelationId,
 			binary_upgrade_next_index_relfilenode = InvalidOid;
 		}
 		else
-			indexRelationId = GetNewRelFileNode(tableSpaceId, pg_class);
+		{
+			indexRelationId =
+				GetNewRelFileNode(tableSpaceId, pg_class,
+								  heapRelation->rd_istemp ?
+									MyBackendId : InvalidBackendId);
+		}
 	}
 
 	/*
diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index ad376a1..4515741 100644
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -52,7 +52,7 @@
 typedef struct PendingRelDelete
 {
 	RelFileNode relnode;		/* relation that may need to be deleted */
-	bool		isTemp;			/* is it a temporary relation? */
+	BackendId	backend;		/* InvalidBackendId if not a temp rel */
 	bool		atCommit;		/* T=delete at commit; F=delete at abort */
 	int			nestLevel;		/* xact nesting level of request */
 	struct PendingRelDelete *next;		/* linked-list link */
@@ -102,8 +102,9 @@ RelationCreateStorage(RelFileNode rnode, bool istemp)
 	XLogRecData rdata;
 	xl_smgr_create xlrec;
 	SMgrRelation srel;
+	BackendId	backend = istemp ? MyBackendId : InvalidBackendId;
 
-	srel = smgropen(rnode);
+	srel = smgropen(rnode, backend);
 	smgrcreate(srel, MAIN_FORKNUM, false);
 
 	if (!istemp)
@@ -125,7 +126,7 @@ RelationCreateStorage(RelFileNode rnode, bool istemp)
 	pending = (PendingRelDelete *)
 		MemoryContextAlloc(TopMemoryContext, sizeof(PendingRelDelete));
 	pending->relnode = rnode;
-	pending->isTemp = istemp;
+	pending->backend = backend;
 	pending->atCommit = false;	/* delete if abort */
 	pending->nestLevel = GetCurrentTransactionNestLevel();
 	pending->next = pendingDeletes;
@@ -145,7 +146,7 @@ RelationDropStorage(Relation rel)
 	pending = (PendingRelDelete *)
 		MemoryContextAlloc(TopMemoryContext, sizeof(PendingRelDelete));
 	pending->relnode = rel->rd_node;
-	pending->isTemp = rel->rd_istemp;
+	pending->backend = rel->rd_backend;
 	pending->atCommit = true;	/* delete if commit */
 	pending->nestLevel = GetCurrentTransactionNestLevel();
 	pending->next = pendingDeletes;
@@ -283,7 +284,7 @@ RelationTruncate(Relation rel, BlockNumber nblocks)
 	}
 
 	/* Do the real work */
-	smgrtruncate(rel->rd_smgr, MAIN_FORKNUM, nblocks, rel->rd_istemp);
+	smgrtruncate(rel->rd_smgr, MAIN_FORKNUM, nblocks);
 }
 
 /*
@@ -322,14 +323,11 @@ smgrDoPendingDeletes(bool isCommit)
 				SMgrRelation srel;
 				int			i;
 
-				srel = smgropen(pending->relnode);
+				srel = smgropen(pending->relnode, pending->backend);
 				for (i = 0; i <= MAX_FORKNUM; i++)
 				{
 					if (smgrexists(srel, i))
-						smgrdounlink(srel,
-									 i,
-									 pending->isTemp,
-									 false);
+						smgrdounlink(srel, i, false);
 				}
 				smgrclose(srel);
 			}
@@ -341,20 +339,24 @@ smgrDoPendingDeletes(bool isCommit)
 }
 
 /*
- * smgrGetPendingDeletes() -- Get a list of relations to be deleted.
+ * smgrGetPendingDeletes() -- Get a list of non-temp relations to be deleted.
  *
  * The return value is the number of relations scheduled for termination.
  * *ptr is set to point to a freshly-palloc'd array of RelFileNodes.
  * If there are no relations to be deleted, *ptr is set to NULL.
  *
- * If haveNonTemp isn't NULL, the bool it points to gets set to true if
- * there is any non-temp table pending to be deleted; false if not.
+ * Only non-temporary relations are included in the returned list.  This is OK
+ * because the list is used only in contexts where temporary relations don't
+ * matter: we're either writing to the two-phase state file (and transactions
+ * that have touched temp tables can't be prepared) or we're writing to xlog
+ * (and all temporary files will be zapped if we restart anyway, so no need
+ * for redo to do it also).
  *
  * Note that the list does not include anything scheduled for termination
  * by upper-level transactions.
  */
 int
-smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr, bool *haveNonTemp)
+smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr)
 {
 	int			nestLevel = GetCurrentTransactionNestLevel();
 	int			nrels;
@@ -362,11 +364,10 @@ smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr, bool *haveNonTemp)
 	PendingRelDelete *pending;
 
 	nrels = 0;
-	if (haveNonTemp)
-		*haveNonTemp = false;
 	for (pending = pendingDeletes; pending != NULL; pending = pending->next)
 	{
-		if (pending->nestLevel >= nestLevel && pending->atCommit == forCommit)
+		if (pending->nestLevel >= nestLevel && pending->atCommit == forCommit
+			&& pending->backend == InvalidBackendId)
 			nrels++;
 	}
 	if (nrels == 0)
@@ -378,13 +379,12 @@ smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr, bool *haveNonTemp)
 	*ptr = rptr;
 	for (pending = pendingDeletes; pending != NULL; pending = pending->next)
 	{
-		if (pending->nestLevel >= nestLevel && pending->atCommit == forCommit)
+		if (pending->nestLevel >= nestLevel && pending->atCommit == forCommit
+			&& pending->backend == InvalidBackendId)
 		{
 			*rptr = pending->relnode;
 			rptr++;
 		}
-		if (haveNonTemp && !pending->isTemp)
-			*haveNonTemp = true;
 	}
 	return nrels;
 }
@@ -456,7 +456,7 @@ smgr_redo(XLogRecPtr lsn, XLogRecord *record)
 		xl_smgr_create *xlrec = (xl_smgr_create *) XLogRecGetData(record);
 		SMgrRelation reln;
 
-		reln = smgropen(xlrec->rnode);
+		reln = smgropen(xlrec->rnode, InvalidBackendId);
 		smgrcreate(reln, MAIN_FORKNUM, true);
 	}
 	else if (info == XLOG_SMGR_TRUNCATE)
@@ -465,7 +465,7 @@ smgr_redo(XLogRecPtr lsn, XLogRecord *record)
 		SMgrRelation reln;
 		Relation	rel;
 
-		reln = smgropen(xlrec->rnode);
+		reln = smgropen(xlrec->rnode, InvalidBackendId);
 
 		/*
 		 * Forcibly create relation if it doesn't exist (which suggests that
@@ -475,7 +475,7 @@ smgr_redo(XLogRecPtr lsn, XLogRecord *record)
 		 */
 		smgrcreate(reln, MAIN_FORKNUM, true);
 
-		smgrtruncate(reln, MAIN_FORKNUM, xlrec->blkno, false);
+		smgrtruncate(reln, MAIN_FORKNUM, xlrec->blkno);
 
 		/* Also tell xlogutils.c about it */
 		XLogTruncateRelation(xlrec->rnode, MAIN_FORKNUM, xlrec->blkno);
@@ -502,7 +502,7 @@ smgr_desc(StringInfo buf, uint8 xl_info, char *rec)
 	if (info == XLOG_SMGR_CREATE)
 	{
 		xl_smgr_create *xlrec = (xl_smgr_create *) rec;
-		char	   *path = relpath(xlrec->rnode, MAIN_FORKNUM);
+		char	   *path = relpathperm(xlrec->rnode, MAIN_FORKNUM);
 
 		appendStringInfo(buf, "file create: %s", path);
 		pfree(path);
@@ -510,7 +510,7 @@ smgr_desc(StringInfo buf, uint8 xl_info, char *rec)
 	else if (info == XLOG_SMGR_TRUNCATE)
 	{
 		xl_smgr_truncate *xlrec = (xl_smgr_truncate *) rec;
-		char	   *path = relpath(xlrec->rnode, MAIN_FORKNUM);
+		char	   *path = relpathperm(xlrec->rnode, MAIN_FORKNUM);
 
 		appendStringInfo(buf, "file truncate: %s to %u blocks", path,
 						 xlrec->blkno);
diff --git a/src/backend/catalog/toasting.c b/src/backend/catalog/toasting.c
index 435dfdd..54cdc4a 100644
--- a/src/backend/catalog/toasting.c
+++ b/src/backend/catalog/toasting.c
@@ -195,7 +195,7 @@ create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid, Datum reloptio
 	 * Toast tables for regular relations go in pg_toast; those for temp
 	 * relations go into the per-backend temp-toast-table namespace.
 	 */
-	if (rel->rd_islocaltemp)
+	if (rel->rd_backend == MyBackendId)
 		namespaceid = GetTempToastNamespace();
 	else
 		namespaceid = PG_TOAST_NAMESPACE;
diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c
index 9d46e47..3d61116 100644
--- a/src/backend/commands/copy.c
+++ b/src/backend/commands/copy.c
@@ -1022,7 +1022,7 @@ DoCopy(const CopyStmt *stmt, const char *queryString)
 		}
 
 		/* 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 f52e1d8..f6867f4 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -470,7 +470,7 @@ 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 */
@@ -747,7 +747,7 @@ 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 5f6fe41..5f6818f 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -6968,13 +6968,13 @@ ATExecSetTableSpace(Oid tableOid, Oid newTableSpace)
 	 * 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);
 
@@ -7056,7 +7056,7 @@ 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
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index 95e9d37..cf79de3 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -113,7 +113,7 @@
  */
 typedef struct
 {
-	RelFileNode rnode;
+	BackendRelFileNode rnode;
 	ForkNumber	forknum;
 	BlockNumber segno;			/* see md.c for special values */
 	/* might add a real request-type field later; not needed yet */
@@ -1071,7 +1071,8 @@ RequestCheckpoint(int flags)
  * than we have to here.
  */
 bool
-ForwardFsyncRequest(RelFileNode rnode, ForkNumber forknum, BlockNumber segno)
+ForwardFsyncRequest(BackendRelFileNode rnode, ForkNumber forknum,
+					BlockNumber segno)
 {
 	BgWriterRequest *request;
 
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index caae936..4dd894b 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -95,7 +95,8 @@ static void WaitIO(volatile BufferDesc *buf);
 static bool StartBufferIO(volatile BufferDesc *buf, bool forInput);
 static void TerminateBufferIO(volatile BufferDesc *buf, bool clear_dirty,
 				  int set_flag_bits);
-static void buffer_write_error_callback(void *arg);
+static void shared_buffer_write_error_callback(void *arg);
+static void local_buffer_write_error_callback(void *arg);
 static volatile BufferDesc *BufferAlloc(SMgrRelation smgr, ForkNumber forkNum,
 			BlockNumber blockNum,
 			BufferAccessStrategy strategy,
@@ -141,7 +142,8 @@ PrefetchBuffer(Relation reln, ForkNumber forkNum, BlockNumber blockNum)
 		int			buf_id;
 
 		/* create a tag so we can lookup the buffer */
-		INIT_BUFFERTAG(newTag, reln->rd_smgr->smgr_rnode, forkNum, blockNum);
+		INIT_BUFFERTAG(newTag, reln->rd_smgr->smgr_rnode.node,
+					   forkNum, blockNum);
 
 		/* determine its hash code and partition lock ID */
 		newHash = BufTableHashCode(&newTag);
@@ -251,18 +253,21 @@ ReadBufferExtended(Relation reln, ForkNumber forkNum, BlockNumber blockNum,
  * ReadBufferWithoutRelcache -- like ReadBufferExtended, but doesn't require
  *		a relcache entry for the relation.
  *
- * NB: caller is assumed to know what it's doing if isTemp is true.
+ * NB: At present, this function may not be used on temporary relations, which
+ * is OK, because we only use it during XLOG replay.  If in the future we
+ * want to use it on temporary relations, we could pass the backend ID as an
+ * additional parameter.
  */
 Buffer
-ReadBufferWithoutRelcache(RelFileNode rnode, bool isTemp,
-						  ForkNumber forkNum, BlockNumber blockNum,
-						  ReadBufferMode mode, BufferAccessStrategy strategy)
+ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
+						  BlockNumber blockNum, ReadBufferMode mode,
+						  BufferAccessStrategy strategy)
 {
 	bool		hit;
 
-	SMgrRelation smgr = smgropen(rnode);
+	SMgrRelation smgr = smgropen(rnode, InvalidBackendId);
 
-	return ReadBuffer_common(smgr, isTemp, forkNum, blockNum, mode, strategy,
+	return ReadBuffer_common(smgr, false, forkNum, blockNum, mode, strategy,
 							 &hit);
 }
 
@@ -414,7 +419,7 @@ ReadBuffer_common(SMgrRelation smgr, bool isLocalBuf, ForkNumber forkNum,
 	{
 		/* new buffers are zero-filled */
 		MemSet((char *) bufBlock, 0, BLCKSZ);
-		smgrextend(smgr, forkNum, blockNum, (char *) bufBlock, isLocalBuf);
+		smgrextend(smgr, forkNum, blockNum, (char *) bufBlock, false);
 	}
 	else
 	{
@@ -465,10 +470,10 @@ ReadBuffer_common(SMgrRelation smgr, bool isLocalBuf, ForkNumber forkNum,
 		VacuumCostBalance += VacuumCostPageMiss;
 
 	TRACE_POSTGRESQL_BUFFER_READ_DONE(forkNum, blockNum,
-									  smgr->smgr_rnode.spcNode,
-									  smgr->smgr_rnode.dbNode,
-									  smgr->smgr_rnode.relNode,
-									  isLocalBuf,
+									  smgr->smgr_rnode.node.spcNode,
+									  smgr->smgr_rnode.node.dbNode,
+									  smgr->smgr_rnode.node.relNode,
+									  smgr->smgr_rnode.backend,
 									  isExtend,
 									  found);
 
@@ -512,7 +517,7 @@ BufferAlloc(SMgrRelation smgr, ForkNumber forkNum,
 	bool		valid;
 
 	/* create a tag so we can lookup the buffer */
-	INIT_BUFFERTAG(newTag, smgr->smgr_rnode, forkNum, blockNum);
+	INIT_BUFFERTAG(newTag, smgr->smgr_rnode.node, forkNum, blockNum);
 
 	/* determine its hash code and partition lock ID */
 	newHash = BufTableHashCode(&newTag);
@@ -1693,21 +1698,24 @@ PrintBufferLeakWarning(Buffer buffer)
 	volatile BufferDesc *buf;
 	int32		loccount;
 	char	   *path;
+	BackendId	backend;
 
 	Assert(BufferIsValid(buffer));
 	if (BufferIsLocal(buffer))
 	{
 		buf = &LocalBufferDescriptors[-buffer - 1];
 		loccount = LocalRefCount[-buffer - 1];
+		backend = MyBackendId;
 	}
 	else
 	{
 		buf = &BufferDescriptors[buffer - 1];
 		loccount = PrivateRefCount[buffer - 1];
+		backend = InvalidBackendId;
 	}
 
 	/* theoretically we should lock the bufhdr here */
-	path = relpath(buf->tag.rnode, buf->tag.forkNum);
+	path = relpathbackend(buf->tag.rnode, backend, buf->tag.forkNum);
 	elog(WARNING,
 		 "buffer refcount leak: [%03d] "
 		 "(rel=%s, blockNum=%u, flags=0x%x, refcount=%u %d)",
@@ -1831,14 +1839,14 @@ FlushBuffer(volatile BufferDesc *buf, SMgrRelation reln)
 		return;
 
 	/* Setup error traceback support for ereport() */
-	errcontext.callback = buffer_write_error_callback;
+	errcontext.callback = shared_buffer_write_error_callback;
 	errcontext.arg = (void *) buf;
 	errcontext.previous = error_context_stack;
 	error_context_stack = &errcontext;
 
 	/* Find smgr relation for buffer */
 	if (reln == NULL)
-		reln = smgropen(buf->tag.rnode);
+		reln = smgropen(buf->tag.rnode, InvalidBackendId);
 
 	TRACE_POSTGRESQL_BUFFER_FLUSH_START(buf->tag.forkNum,
 										buf->tag.blockNum,
@@ -1929,14 +1937,15 @@ RelationGetNumberOfBlocks(Relation relation)
  * --------------------------------------------------------------------
  */
 void
-DropRelFileNodeBuffers(RelFileNode rnode, ForkNumber forkNum, bool istemp,
+DropRelFileNodeBuffers(BackendRelFileNode rnode, ForkNumber forkNum,
 					   BlockNumber firstDelBlock)
 {
 	int			i;
 
-	if (istemp)
+	if (rnode.backend != InvalidBackendId)
 	{
-		DropRelFileNodeLocalBuffers(rnode, forkNum, firstDelBlock);
+		if (rnode.backend == MyBackendId)
+			DropRelFileNodeLocalBuffers(rnode.node, forkNum, firstDelBlock);
 		return;
 	}
 
@@ -1945,7 +1954,7 @@ DropRelFileNodeBuffers(RelFileNode rnode, ForkNumber forkNum, bool istemp,
 		volatile BufferDesc *bufHdr = &BufferDescriptors[i];
 
 		LockBufHdr(bufHdr);
-		if (RelFileNodeEquals(bufHdr->tag.rnode, rnode) &&
+		if (RelFileNodeEquals(bufHdr->tag.rnode, rnode.node) &&
 			bufHdr->tag.forkNum == forkNum &&
 			bufHdr->tag.blockNum >= firstDelBlock)
 			InvalidateBuffer(bufHdr);	/* releases spinlock */
@@ -2008,7 +2017,7 @@ PrintBufferDescs(void)
 			 "[%02d] (freeNext=%d, rel=%s, "
 			 "blockNum=%u, flags=0x%x, refcount=%u %d)",
 			 i, buf->freeNext,
-			 relpath(buf->tag.rnode, buf->tag.forkNum),
+			 relpathbackend(buf->tag.rnode, InvalidBackendId, buf->tag.forkNum),
 			 buf->tag.blockNum, buf->flags,
 			 buf->refcount, PrivateRefCount[i]);
 	}
@@ -2078,7 +2087,7 @@ FlushRelationBuffers(Relation rel)
 				ErrorContextCallback errcontext;
 
 				/* Setup error traceback support for ereport() */
-				errcontext.callback = buffer_write_error_callback;
+				errcontext.callback = local_buffer_write_error_callback;
 				errcontext.arg = (void *) bufHdr;
 				errcontext.previous = error_context_stack;
 				error_context_stack = &errcontext;
@@ -2087,7 +2096,7 @@ FlushRelationBuffers(Relation rel)
 						  bufHdr->tag.forkNum,
 						  bufHdr->tag.blockNum,
 						  (char *) LocalBufHdrGetBlock(bufHdr),
-						  true);
+						  false);
 
 				bufHdr->flags &= ~(BM_DIRTY | BM_JUST_DIRTIED);
 
@@ -2699,8 +2708,9 @@ AbortBufferIO(void)
 			if (sv_flags & BM_IO_ERROR)
 			{
 				/* Buffer is pinned, so we can read tag without spinlock */
-				char	   *path = relpath(buf->tag.rnode, buf->tag.forkNum);
+				char	   *path;
 
+				path = relpathperm(buf->tag.rnode, buf->tag.forkNum);
 				ereport(WARNING,
 						(errcode(ERRCODE_IO_ERROR),
 						 errmsg("could not write block %u of %s",
@@ -2714,17 +2724,36 @@ AbortBufferIO(void)
 }
 
 /*
- * Error context callback for errors occurring during buffer writes.
+ * Error context callback for errors occurring during shared buffer writes.
  */
 static void
-buffer_write_error_callback(void *arg)
+shared_buffer_write_error_callback(void *arg)
 {
 	volatile BufferDesc *bufHdr = (volatile BufferDesc *) arg;
 
 	/* Buffer is pinned, so we can read the tag without locking the spinlock */
 	if (bufHdr != NULL)
 	{
-		char	   *path = relpath(bufHdr->tag.rnode, bufHdr->tag.forkNum);
+		char	   *path = relpathperm(bufHdr->tag.rnode, bufHdr->tag.forkNum);
+
+		errcontext("writing block %u of relation %s",
+				   bufHdr->tag.blockNum, path);
+		pfree(path);
+	}
+}
+
+/*
+ * Error context callback for errors occurring during buffer writes.
+ */
+static void
+local_buffer_write_error_callback(void *arg)
+{
+	volatile BufferDesc *bufHdr = (volatile BufferDesc *) arg;
+
+	if (bufHdr != NULL)
+	{
+		char	   *path = relpathbackend(bufHdr->tag.rnode, MyBackendId,
+										 bufHdr->tag.forkNum);
 
 		errcontext("writing block %u of relation %s",
 				   bufHdr->tag.blockNum, path);
diff --git a/src/backend/storage/buffer/localbuf.c b/src/backend/storage/buffer/localbuf.c
index c5b6a2c..bbf0a01 100644
--- a/src/backend/storage/buffer/localbuf.c
+++ b/src/backend/storage/buffer/localbuf.c
@@ -68,7 +68,7 @@ LocalPrefetchBuffer(SMgrRelation smgr, ForkNumber forkNum,
 	BufferTag	newTag;			/* identity of requested block */
 	LocalBufferLookupEnt *hresult;
 
-	INIT_BUFFERTAG(newTag, smgr->smgr_rnode, forkNum, blockNum);
+	INIT_BUFFERTAG(newTag, smgr->smgr_rnode.node, forkNum, blockNum);
 
 	/* Initialize local buffers if first request in this session */
 	if (LocalBufHash == NULL)
@@ -110,7 +110,7 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
 	int			trycounter;
 	bool		found;
 
-	INIT_BUFFERTAG(newTag, smgr->smgr_rnode, forkNum, blockNum);
+	INIT_BUFFERTAG(newTag, smgr->smgr_rnode.node, forkNum, blockNum);
 
 	/* Initialize local buffers if first request in this session */
 	if (LocalBufHash == NULL)
@@ -127,7 +127,7 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
 		Assert(BUFFERTAGS_EQUAL(bufHdr->tag, newTag));
 #ifdef LBDEBUG
 		fprintf(stderr, "LB ALLOC (%u,%d,%d) %d\n",
-				smgr->smgr_rnode.relNode, forkNum, blockNum, -b - 1);
+				smgr->smgr_rnode.node.relNode, forkNum, blockNum, -b - 1);
 #endif
 		/* this part is equivalent to PinBuffer for a shared buffer */
 		if (LocalRefCount[b] == 0)
@@ -150,7 +150,8 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
 
 #ifdef LBDEBUG
 	fprintf(stderr, "LB ALLOC (%u,%d,%d) %d\n",
-		 smgr->smgr_rnode.relNode, forkNum, blockNum, -nextFreeLocalBuf - 1);
+		 smgr->smgr_rnode.node.relNode, forkNum, blockNum,
+		 -nextFreeLocalBuf - 1);
 #endif
 
 	/*
@@ -198,14 +199,14 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
 		SMgrRelation oreln;
 
 		/* Find smgr relation for buffer */
-		oreln = smgropen(bufHdr->tag.rnode);
+		oreln = smgropen(bufHdr->tag.rnode, MyBackendId);
 
 		/* And write... */
 		smgrwrite(oreln,
 				  bufHdr->tag.forkNum,
 				  bufHdr->tag.blockNum,
 				  (char *) LocalBufHdrGetBlock(bufHdr),
-				  true);
+				  false);
 
 		/* Mark not-dirty now in case we error out below */
 		bufHdr->flags &= ~BM_DIRTY;
@@ -309,7 +310,8 @@ DropRelFileNodeLocalBuffers(RelFileNode rnode, ForkNumber forkNum,
 			if (LocalRefCount[i] != 0)
 				elog(ERROR, "block %u of %s is still referenced (local %u)",
 					 bufHdr->tag.blockNum,
-					 relpath(bufHdr->tag.rnode, bufHdr->tag.forkNum),
+					 relpathbackend(bufHdr->tag.rnode, MyBackendId,
+								   bufHdr->tag.forkNum),
 					 LocalRefCount[i]);
 			/* Remove entry from hashtable */
 			hresult = (LocalBufferLookupEnt *)
diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c
index 1d2eeec..3fb5844 100644
--- a/src/backend/storage/file/fd.c
+++ b/src/backend/storage/file/fd.c
@@ -249,6 +249,9 @@ static File OpenTemporaryFileInTablespace(Oid tblspcOid, bool rejectError);
 static void AtProcExit_Files(int code, Datum arg);
 static void CleanupTempFiles(bool isProcExit);
 static void RemovePgTempFilesInDir(const char *tmpdirname);
+static void RemovePgTempRelationFiles(const char *tsdirname);
+static void RemovePgTempRelationFilesInDbspace(const char *dbspacedirname);
+static bool looks_like_temp_rel_name(const char *name);
 
 
 /*
@@ -1824,10 +1827,12 @@ CleanupTempFiles(bool isProcExit)
 
 
 /*
- * Remove temporary files left over from a prior postmaster session
+ * Remove temporary and temporary relation files left over from a prior
+ * postmaster session
  *
  * This should be called during postmaster startup.  It will forcibly
- * remove any leftover files created by OpenTemporaryFile.
+ * remove any leftover files created by OpenTemporaryFile and any leftover
+ * temporary relation files created by mdcreate.
  *
  * NOTE: we could, but don't, call this during a post-backend-crash restart
  * cycle.  The argument for not doing it is that someone might want to examine
@@ -1847,6 +1852,7 @@ RemovePgTempFiles(void)
 	 */
 	snprintf(temp_path, sizeof(temp_path), "base/%s", PG_TEMP_FILES_DIR);
 	RemovePgTempFilesInDir(temp_path);
+	RemovePgTempRelationFiles("base");
 
 	/*
 	 * Cycle through temp directories for all non-default tablespaces.
@@ -1862,6 +1868,10 @@ RemovePgTempFiles(void)
 		snprintf(temp_path, sizeof(temp_path), "pg_tblspc/%s/%s/%s",
 			spc_de->d_name, TABLESPACE_VERSION_DIRECTORY, PG_TEMP_FILES_DIR);
 		RemovePgTempFilesInDir(temp_path);
+
+		snprintf(temp_path, sizeof(temp_path), "pg_tblspc/%s/%s",
+			spc_de->d_name, TABLESPACE_VERSION_DIRECTORY);
+		RemovePgTempRelationFiles(temp_path);
 	}
 
 	FreeDir(spc_dir);
@@ -1915,3 +1925,123 @@ RemovePgTempFilesInDir(const char *tmpdirname)
 
 	FreeDir(temp_dir);
 }
+
+/* Process one tablespace directory, look for per-DB subdirectories */
+static void
+RemovePgTempRelationFiles(const char *tsdirname)
+{
+	DIR		   *ts_dir;
+	struct dirent *de;
+	char		dbspace_path[MAXPGPATH];
+
+	ts_dir = AllocateDir(tsdirname);
+	if (ts_dir == NULL)
+	{
+		/* anything except ENOENT is fishy */
+		if (errno != ENOENT)
+			elog(LOG,
+				 "could not open tablespace directory \"%s\": %m",
+				 tsdirname);
+		return;
+	}
+
+	while ((de = ReadDir(ts_dir, tsdirname)) != NULL)
+	{
+		int		i = 0;
+
+		/*
+		 * We're only interested in the per-database directories, which have
+		 * numeric names.  Note that this code will also (properly) ignore "."
+		 * and "..".
+		 */
+		while (isdigit((unsigned char) de->d_name[i]))
+			++i;
+		if (de->d_name[i] != '\0' || i == 0)
+			continue;
+
+		snprintf(dbspace_path, sizeof(dbspace_path), "%s/%s",
+				 tsdirname, de->d_name);
+		RemovePgTempRelationFilesInDbspace(dbspace_path);
+	}
+
+	FreeDir(ts_dir);
+}
+
+/* Process one per-dbspace directory for RemovePgTempRelationFiles */
+static void
+RemovePgTempRelationFilesInDbspace(const char *dbspacedirname)
+{
+	DIR		   *dbspace_dir;
+	struct dirent *de;
+	char		rm_path[MAXPGPATH];
+
+	dbspace_dir = AllocateDir(dbspacedirname);
+	if (dbspace_dir == NULL)
+	{
+		/* we just saw this directory, so it really ought to be there */
+		elog(LOG,
+			 "could not open dbspace directory \"%s\": %m",
+			 dbspacedirname);
+		return;
+	}
+
+	while ((de = ReadDir(dbspace_dir, dbspacedirname)) != NULL)
+	{
+		if (!looks_like_temp_rel_name(de->d_name))
+			continue;
+
+		snprintf(rm_path, sizeof(rm_path), "%s/%s",
+				 dbspacedirname, de->d_name);
+
+		unlink(rm_path);	/* note we ignore any error */
+	}
+
+	FreeDir(dbspace_dir);
+}
+
+/* t<digits>_<digits>, or t<digits>_<digits>_<forkname> */
+static bool
+looks_like_temp_rel_name(const char *name)
+{
+	int			pos;
+	int			savepos;
+
+	/* Must start with "t". */
+	if (name[0] != 't')
+		return false;
+
+	/* Followed by a non-empty string of digits and then an underscore. */
+	for (pos = 1; isdigit((unsigned char) name[pos]); ++pos)
+		;
+	if (pos == 1 || name[pos] != '_')
+		return false;
+
+	/* Followed by another nonempty string of digits. */
+	for (savepos = ++pos; isdigit((unsigned char) name[pos]); ++pos)
+		;
+	if (savepos == pos)
+		return false;
+
+	/* We might have _forkname or .segment or both. */
+	if (name[pos] == '_')
+	{
+		int		forkchar = forkname_chars(&name[pos+1]);
+		if (forkchar <= 0)
+			return false;
+		pos += forkchar + 1;
+	}
+	if (name[pos] == '.')
+	{
+		int		segchar;
+		for (segchar = 1; isdigit((unsigned char) name[pos+segchar]); ++segchar)
+			;
+		if (segchar <= 1)
+			return false;
+		pos += segchar;
+	}
+
+	/* Now we should be at the end. */
+	if (name[pos] != '\0')
+		return false;
+	return true;
+}
diff --git a/src/backend/storage/freespace/freespace.c b/src/backend/storage/freespace/freespace.c
index 579572f..b43a2ce 100644
--- a/src/backend/storage/freespace/freespace.c
+++ b/src/backend/storage/freespace/freespace.c
@@ -303,7 +303,7 @@ FreeSpaceMapTruncateRel(Relation rel, BlockNumber nblocks)
 	}
 
 	/* Truncate the unused FSM pages, and send smgr inval message */
-	smgrtruncate(rel->rd_smgr, FSM_FORKNUM, new_nfsmblocks, rel->rd_istemp);
+	smgrtruncate(rel->rd_smgr, FSM_FORKNUM, new_nfsmblocks);
 
 	/*
 	 * We might as well update the local smgr_fsm_nblocks setting.
diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.c
index 4163ca0..79805b4 100644
--- a/src/backend/storage/smgr/md.c
+++ b/src/backend/storage/smgr/md.c
@@ -119,7 +119,7 @@ static MemoryContext MdCxt;		/* context for all md.c allocations */
  */
 typedef struct
 {
-	RelFileNode rnode;			/* the targeted relation */
+	BackendRelFileNode rnode;	/* the targeted relation */
 	ForkNumber	forknum;
 	BlockNumber segno;			/* which segment */
 } PendingOperationTag;
@@ -135,7 +135,7 @@ typedef struct
 
 typedef struct
 {
-	RelFileNode rnode;			/* the dead relation to delete */
+	BackendRelFileNode rnode;	/* the dead relation to delete */
 	CycleCtr	cycle_ctr;		/* mdckpt_cycle_ctr when request was made */
 } PendingUnlinkEntry;
 
@@ -158,14 +158,14 @@ static MdfdVec *mdopen(SMgrRelation reln, ForkNumber forknum,
 	   ExtensionBehavior behavior);
 static void register_dirty_segment(SMgrRelation reln, ForkNumber forknum,
 					   MdfdVec *seg);
-static void register_unlink(RelFileNode rnode);
+static void register_unlink(BackendRelFileNode rnode);
 static MdfdVec *_fdvec_alloc(void);
 static char *_mdfd_segpath(SMgrRelation reln, ForkNumber forknum,
 			  BlockNumber segno);
 static MdfdVec *_mdfd_openseg(SMgrRelation reln, ForkNumber forkno,
 			  BlockNumber segno, int oflags);
 static MdfdVec *_mdfd_getseg(SMgrRelation reln, ForkNumber forkno,
-			 BlockNumber blkno, bool isTemp, ExtensionBehavior behavior);
+			 BlockNumber blkno, bool skipFsync, ExtensionBehavior behavior);
 static BlockNumber _mdnblocks(SMgrRelation reln, ForkNumber forknum,
 		   MdfdVec *seg);
 
@@ -321,7 +321,7 @@ mdcreate(SMgrRelation reln, ForkNumber forkNum, bool isRedo)
  * we are usually not in a transaction anymore when this is called.
  */
 void
-mdunlink(RelFileNode rnode, ForkNumber forkNum, bool isRedo)
+mdunlink(BackendRelFileNode rnode, ForkNumber forkNum, bool isRedo)
 {
 	char	   *path;
 	int			ret;
@@ -417,7 +417,7 @@ mdunlink(RelFileNode rnode, ForkNumber forkNum, bool isRedo)
  */
 void
 mdextend(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
-		 char *buffer, bool isTemp)
+		 char *buffer, bool skipFsync)
 {
 	off_t		seekpos;
 	int			nbytes;
@@ -440,7 +440,7 @@ mdextend(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 						relpath(reln->smgr_rnode, forknum),
 						InvalidBlockNumber)));
 
-	v = _mdfd_getseg(reln, forknum, blocknum, isTemp, EXTENSION_CREATE);
+	v = _mdfd_getseg(reln, forknum, blocknum, skipFsync, EXTENSION_CREATE);
 
 	seekpos = (off_t) BLCKSZ *(blocknum % ((BlockNumber) RELSEG_SIZE));
 
@@ -478,7 +478,7 @@ mdextend(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 				 errhint("Check free disk space.")));
 	}
 
-	if (!isTemp)
+	if (!skipFsync && !SmgrIsTemp(reln))
 		register_dirty_segment(reln, forknum, v);
 
 	Assert(_mdnblocks(reln, forknum, v) <= ((BlockNumber) RELSEG_SIZE));
@@ -605,9 +605,10 @@ mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 	MdfdVec    *v;
 
 	TRACE_POSTGRESQL_SMGR_MD_READ_START(forknum, blocknum,
-										reln->smgr_rnode.spcNode,
-										reln->smgr_rnode.dbNode,
-										reln->smgr_rnode.relNode);
+										reln->smgr_rnode.node.spcNode,
+										reln->smgr_rnode.node.dbNode,
+										reln->smgr_rnode.node.relNode,
+										reln->smgr_rnode.backend);
 
 	v = _mdfd_getseg(reln, forknum, blocknum, false, EXTENSION_FAIL);
 
@@ -624,9 +625,10 @@ mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 	nbytes = FileRead(v->mdfd_vfd, buffer, BLCKSZ);
 
 	TRACE_POSTGRESQL_SMGR_MD_READ_DONE(forknum, blocknum,
-									   reln->smgr_rnode.spcNode,
-									   reln->smgr_rnode.dbNode,
-									   reln->smgr_rnode.relNode,
+									   reln->smgr_rnode.node.spcNode,
+									   reln->smgr_rnode.node.dbNode,
+									   reln->smgr_rnode.node.relNode,
+									   reln->smgr_rnode.backend,
 									   nbytes,
 									   BLCKSZ);
 
@@ -666,7 +668,7 @@ mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
  */
 void
 mdwrite(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
-		char *buffer, bool isTemp)
+		char *buffer, bool skipFsync)
 {
 	off_t		seekpos;
 	int			nbytes;
@@ -678,11 +680,12 @@ mdwrite(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 #endif
 
 	TRACE_POSTGRESQL_SMGR_MD_WRITE_START(forknum, blocknum,
-										 reln->smgr_rnode.spcNode,
-										 reln->smgr_rnode.dbNode,
-										 reln->smgr_rnode.relNode);
+										 reln->smgr_rnode.node.spcNode,
+										 reln->smgr_rnode.node.dbNode,
+										 reln->smgr_rnode.node.relNode,
+										 reln->smgr_rnode.backend);
 
-	v = _mdfd_getseg(reln, forknum, blocknum, isTemp, EXTENSION_FAIL);
+	v = _mdfd_getseg(reln, forknum, blocknum, skipFsync, EXTENSION_FAIL);
 
 	seekpos = (off_t) BLCKSZ *(blocknum % ((BlockNumber) RELSEG_SIZE));
 
@@ -697,9 +700,10 @@ mdwrite(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 	nbytes = FileWrite(v->mdfd_vfd, buffer, BLCKSZ);
 
 	TRACE_POSTGRESQL_SMGR_MD_WRITE_DONE(forknum, blocknum,
-										reln->smgr_rnode.spcNode,
-										reln->smgr_rnode.dbNode,
-										reln->smgr_rnode.relNode,
+										reln->smgr_rnode.node.spcNode,
+										reln->smgr_rnode.node.dbNode,
+										reln->smgr_rnode.node.relNode,
+										reln->smgr_rnode.backend,
 										nbytes,
 										BLCKSZ);
 
@@ -720,7 +724,7 @@ mdwrite(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 				 errhint("Check free disk space.")));
 	}
 
-	if (!isTemp)
+	if (!skipFsync && !SmgrIsTemp(reln))
 		register_dirty_segment(reln, forknum, v);
 }
 
@@ -794,8 +798,7 @@ mdnblocks(SMgrRelation reln, ForkNumber forknum)
  *	mdtruncate() -- Truncate relation to specified number of blocks.
  */
 void
-mdtruncate(SMgrRelation reln, ForkNumber forknum, BlockNumber nblocks,
-		   bool isTemp)
+mdtruncate(SMgrRelation reln, ForkNumber forknum, BlockNumber nblocks)
 {
 	MdfdVec    *v;
 	BlockNumber curnblk;
@@ -839,7 +842,7 @@ mdtruncate(SMgrRelation reln, ForkNumber forknum, BlockNumber nblocks,
 						 errmsg("could not truncate file \"%s\": %m",
 								FilePathName(v->mdfd_vfd))));
 
-			if (!isTemp)
+			if (!SmgrIsTemp(reln))
 				register_dirty_segment(reln, forknum, v);
 			v = v->mdfd_chain;
 			Assert(ov != reln->md_fd[forknum]); /* we never drop the 1st
@@ -864,7 +867,7 @@ mdtruncate(SMgrRelation reln, ForkNumber forknum, BlockNumber nblocks,
 					errmsg("could not truncate file \"%s\" to %u blocks: %m",
 						   FilePathName(v->mdfd_vfd),
 						   nblocks)));
-			if (!isTemp)
+			if (!SmgrIsTemp(reln))
 				register_dirty_segment(reln, forknum, v);
 			v = v->mdfd_chain;
 			ov->mdfd_chain = NULL;
@@ -1052,7 +1055,8 @@ mdsync(void)
 				 * the relation will have been dirtied through this same smgr
 				 * relation, and so we can save a file open/close cycle.
 				 */
-				reln = smgropen(entry->tag.rnode);
+				reln = smgropen(entry->tag.rnode.node,
+								entry->tag.rnode.backend);
 
 				/*
 				 * It is possible that the relation has been dropped or
@@ -1235,7 +1239,7 @@ register_dirty_segment(SMgrRelation reln, ForkNumber forknum, MdfdVec *seg)
  * a remote pending-ops table.
  */
 static void
-register_unlink(RelFileNode rnode)
+register_unlink(BackendRelFileNode rnode)
 {
 	if (pendingOpsTable)
 	{
@@ -1278,7 +1282,8 @@ register_unlink(RelFileNode rnode)
  * structure for them.)
  */
 void
-RememberFsyncRequest(RelFileNode rnode, ForkNumber forknum, BlockNumber segno)
+RememberFsyncRequest(BackendRelFileNode rnode, ForkNumber forknum,
+					 BlockNumber segno)
 {
 	Assert(pendingOpsTable);
 
@@ -1291,7 +1296,7 @@ RememberFsyncRequest(RelFileNode rnode, ForkNumber forknum, BlockNumber segno)
 		hash_seq_init(&hstat, pendingOpsTable);
 		while ((entry = (PendingOperationEntry *) hash_seq_search(&hstat)) != NULL)
 		{
-			if (RelFileNodeEquals(entry->tag.rnode, rnode) &&
+			if (BackendRelFileNodeEquals(entry->tag.rnode, rnode) &&
 				entry->tag.forknum == forknum)
 			{
 				/* Okay, cancel this entry */
@@ -1312,7 +1317,7 @@ RememberFsyncRequest(RelFileNode rnode, ForkNumber forknum, BlockNumber segno)
 		hash_seq_init(&hstat, pendingOpsTable);
 		while ((entry = (PendingOperationEntry *) hash_seq_search(&hstat)) != NULL)
 		{
-			if (entry->tag.rnode.dbNode == rnode.dbNode)
+			if (entry->tag.rnode.node.dbNode == rnode.node.dbNode)
 			{
 				/* Okay, cancel this entry */
 				entry->canceled = true;
@@ -1326,7 +1331,7 @@ RememberFsyncRequest(RelFileNode rnode, ForkNumber forknum, BlockNumber segno)
 			PendingUnlinkEntry *entry = (PendingUnlinkEntry *) lfirst(cell);
 
 			next = lnext(cell);
-			if (entry->rnode.dbNode == rnode.dbNode)
+			if (entry->rnode.node.dbNode == rnode.node.dbNode)
 			{
 				pendingUnlinks = list_delete_cell(pendingUnlinks, cell, prev);
 				pfree(entry);
@@ -1393,7 +1398,7 @@ RememberFsyncRequest(RelFileNode rnode, ForkNumber forknum, BlockNumber segno)
  * ForgetRelationFsyncRequests -- forget any fsyncs for a rel
  */
 void
-ForgetRelationFsyncRequests(RelFileNode rnode, ForkNumber forknum)
+ForgetRelationFsyncRequests(BackendRelFileNode rnode, ForkNumber forknum)
 {
 	if (pendingOpsTable)
 	{
@@ -1428,11 +1433,12 @@ ForgetRelationFsyncRequests(RelFileNode rnode, ForkNumber forknum)
 void
 ForgetDatabaseFsyncRequests(Oid dbid)
 {
-	RelFileNode rnode;
+	BackendRelFileNode rnode;
 
-	rnode.dbNode = dbid;
-	rnode.spcNode = 0;
-	rnode.relNode = 0;
+	rnode.node.dbNode = dbid;
+	rnode.node.spcNode = 0;
+	rnode.node.relNode = 0;
+	rnode.backend = InvalidBackendId;
 
 	if (pendingOpsTable)
 	{
@@ -1523,12 +1529,12 @@ _mdfd_openseg(SMgrRelation reln, ForkNumber forknum, BlockNumber segno,
  *		specified block.
  *
  * If the segment doesn't exist, we ereport, return NULL, or create the
- * segment, according to "behavior".  Note: isTemp need only be correct
- * in the EXTENSION_CREATE case.
+ * segment, according to "behavior".  Note: skipFsync is only used in the
+ * EXTENSION_CREATE case.
  */
 static MdfdVec *
 _mdfd_getseg(SMgrRelation reln, ForkNumber forknum, BlockNumber blkno,
-			 bool isTemp, ExtensionBehavior behavior)
+			 bool skipFsync, ExtensionBehavior behavior)
 {
 	MdfdVec    *v = mdopen(reln, forknum, behavior);
 	BlockNumber targetseg;
@@ -1566,7 +1572,7 @@ _mdfd_getseg(SMgrRelation reln, ForkNumber forknum, BlockNumber blkno,
 
 					mdextend(reln, forknum,
 							 nextsegno * ((BlockNumber) RELSEG_SIZE) - 1,
-							 zerobuf, isTemp);
+							 zerobuf, skipFsync);
 					pfree(zerobuf);
 				}
 				v->mdfd_chain = _mdfd_openseg(reln, forknum, +nextsegno, O_CREAT);
diff --git a/src/backend/storage/smgr/smgr.c b/src/backend/storage/smgr/smgr.c
index 3b12cb3..ecf238d 100644
--- a/src/backend/storage/smgr/smgr.c
+++ b/src/backend/storage/smgr/smgr.c
@@ -45,19 +45,19 @@ typedef struct f_smgr
 	void		(*smgr_create) (SMgrRelation reln, ForkNumber forknum,
 											bool isRedo);
 	bool		(*smgr_exists) (SMgrRelation reln, ForkNumber forknum);
-	void		(*smgr_unlink) (RelFileNode rnode, ForkNumber forknum,
+	void		(*smgr_unlink) (BackendRelFileNode rnode, ForkNumber forknum,
 											bool isRedo);
 	void		(*smgr_extend) (SMgrRelation reln, ForkNumber forknum,
-							BlockNumber blocknum, char *buffer, bool isTemp);
+							BlockNumber blocknum, char *buffer, bool skipFsync);
 	void		(*smgr_prefetch) (SMgrRelation reln, ForkNumber forknum,
 											  BlockNumber blocknum);
 	void		(*smgr_read) (SMgrRelation reln, ForkNumber forknum,
 										  BlockNumber blocknum, char *buffer);
 	void		(*smgr_write) (SMgrRelation reln, ForkNumber forknum,
-							BlockNumber blocknum, char *buffer, bool isTemp);
+							BlockNumber blocknum, char *buffer, bool skipFsync);
 	BlockNumber (*smgr_nblocks) (SMgrRelation reln, ForkNumber forknum);
 	void		(*smgr_truncate) (SMgrRelation reln, ForkNumber forknum,
-										   BlockNumber nblocks, bool isTemp);
+										   BlockNumber nblocks);
 	void		(*smgr_immedsync) (SMgrRelation reln, ForkNumber forknum);
 	void		(*smgr_pre_ckpt) (void);		/* may be NULL */
 	void		(*smgr_sync) (void);	/* may be NULL */
@@ -83,8 +83,6 @@ static HTAB *SMgrRelationHash = NULL;
 
 /* local function prototypes */
 static void smgrshutdown(int code, Datum arg);
-static void smgr_internal_unlink(RelFileNode rnode, ForkNumber forknum,
-					 int which, bool isTemp, bool isRedo);
 
 
 /*
@@ -131,8 +129,9 @@ smgrshutdown(int code, Datum arg)
  *		This does not attempt to actually open the object.
  */
 SMgrRelation
-smgropen(RelFileNode rnode)
+smgropen(RelFileNode rnode, BackendId backend)
 {
+	BackendRelFileNode brnode;
 	SMgrRelation reln;
 	bool		found;
 
@@ -142,7 +141,7 @@ smgropen(RelFileNode rnode)
 		HASHCTL		ctl;
 
 		MemSet(&ctl, 0, sizeof(ctl));
-		ctl.keysize = sizeof(RelFileNode);
+		ctl.keysize = sizeof(BackendRelFileNode);
 		ctl.entrysize = sizeof(SMgrRelationData);
 		ctl.hash = tag_hash;
 		SMgrRelationHash = hash_create("smgr relation table", 400,
@@ -150,8 +149,10 @@ smgropen(RelFileNode rnode)
 	}
 
 	/* Look up or create an entry */
+	brnode.node = rnode;
+	brnode.backend = backend;
 	reln = (SMgrRelation) hash_search(SMgrRelationHash,
-									  (void *) &rnode,
+									  (void *) &brnode,
 									  HASH_ENTER, &found);
 
 	/* Initialize it if not present before */
@@ -261,7 +262,7 @@ smgrcloseall(void)
  * such entry exists already.
  */
 void
-smgrclosenode(RelFileNode rnode)
+smgrclosenode(BackendRelFileNode rnode)
 {
 	SMgrRelation reln;
 
@@ -305,8 +306,8 @@ smgrcreate(SMgrRelation reln, ForkNumber forknum, bool isRedo)
 	 * should be here and not in commands/tablespace.c?  But that would imply
 	 * importing a lot of stuff that smgr.c oughtn't know, either.
 	 */
-	TablespaceCreateDbspace(reln->smgr_rnode.spcNode,
-							reln->smgr_rnode.dbNode,
+	TablespaceCreateDbspace(reln->smgr_rnode.node.spcNode,
+							reln->smgr_rnode.node.dbNode,
 							isRedo);
 
 	(*(smgrsw[reln->smgr_which].smgr_create)) (reln, forknum, isRedo);
@@ -323,29 +324,19 @@ smgrcreate(SMgrRelation reln, ForkNumber forknum, bool isRedo)
  *		already.
  */
 void
-smgrdounlink(SMgrRelation reln, ForkNumber forknum, bool isTemp, bool isRedo)
+smgrdounlink(SMgrRelation reln, ForkNumber forknum, bool isRedo)
 {
-	RelFileNode rnode = reln->smgr_rnode;
+	BackendRelFileNode rnode = reln->smgr_rnode;
 	int			which = reln->smgr_which;
 
 	/* Close the fork */
 	(*(smgrsw[which].smgr_close)) (reln, forknum);
 
-	smgr_internal_unlink(rnode, forknum, which, isTemp, isRedo);
-}
-
-/*
- * Shared subroutine that actually does the unlink ...
- */
-static void
-smgr_internal_unlink(RelFileNode rnode, ForkNumber forknum,
-					 int which, bool isTemp, bool isRedo)
-{
 	/*
 	 * Get rid of any remaining buffers for the relation.  bufmgr will just
 	 * drop them without bothering to write the contents.
 	 */
-	DropRelFileNodeBuffers(rnode, forknum, isTemp, 0);
+	DropRelFileNodeBuffers(rnode, forknum, 0);
 
 	/*
 	 * It'd be nice to tell the stats collector to forget it immediately, too.
@@ -385,10 +376,10 @@ smgr_internal_unlink(RelFileNode rnode, ForkNumber forknum,
  */
 void
 smgrextend(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
-		   char *buffer, bool isTemp)
+		   char *buffer, bool skipFsync)
 {
 	(*(smgrsw[reln->smgr_which].smgr_extend)) (reln, forknum, blocknum,
-											   buffer, isTemp);
+											   buffer, skipFsync);
 }
 
 /*
@@ -426,16 +417,16 @@ smgrread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
  *		on disk at return, only dumped out to the kernel.  However,
  *		provisions will be made to fsync the write before the next checkpoint.
  *
- *		isTemp indicates that the relation is a temp table (ie, is managed
- *		by the local-buffer manager).  In this case no provisions need be
- *		made to fsync the write before checkpointing.
+ *		skipFsync indicates that the caller will make other provisions to
+ *		fsync the relation, so we needn't bother.  Temporary relations also
+ *		do not require fsync.
  */
 void
 smgrwrite(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
-		  char *buffer, bool isTemp)
+		  char *buffer, bool skipFsync)
 {
 	(*(smgrsw[reln->smgr_which].smgr_write)) (reln, forknum, blocknum,
-											  buffer, isTemp);
+											  buffer, skipFsync);
 }
 
 /*
@@ -455,14 +446,13 @@ smgrnblocks(SMgrRelation reln, ForkNumber forknum)
  * The truncation is done immediately, so this can't be rolled back.
  */
 void
-smgrtruncate(SMgrRelation reln, ForkNumber forknum, BlockNumber nblocks,
-			 bool isTemp)
+smgrtruncate(SMgrRelation reln, ForkNumber forknum, BlockNumber nblocks)
 {
 	/*
 	 * Get rid of any buffers for the about-to-be-deleted blocks. bufmgr will
 	 * just drop them without bothering to write the contents.
 	 */
-	DropRelFileNodeBuffers(reln->smgr_rnode, forknum, isTemp, nblocks);
+	DropRelFileNodeBuffers(reln->smgr_rnode, forknum, nblocks);
 
 	/*
 	 * Send a shared-inval message to force other backends to close any smgr
@@ -479,8 +469,7 @@ smgrtruncate(SMgrRelation reln, ForkNumber forknum, BlockNumber nblocks,
 	/*
 	 * Do the truncation.
 	 */
-	(*(smgrsw[reln->smgr_which].smgr_truncate)) (reln, forknum, nblocks,
-												 isTemp);
+	(*(smgrsw[reln->smgr_which].smgr_truncate)) (reln, forknum, nblocks);
 }
 
 /*
@@ -499,7 +488,7 @@ smgrtruncate(SMgrRelation reln, ForkNumber forknum, BlockNumber nblocks,
  *		to use the WAL log for PITR or replication purposes: in that case
  *		we have to make WAL entries as well.)
  *
- *		The preceding writes should specify isTemp = true to avoid
+ *		The preceding writes should specify skipFsync = true to avoid
  *		duplicative fsyncs.
  *
  *		Note that you need to do FlushRelationBuffers() first if there is
diff --git a/src/backend/utils/adt/dbsize.c b/src/backend/utils/adt/dbsize.c
index a4e0252..dac2d72 100644
--- a/src/backend/utils/adt/dbsize.c
+++ b/src/backend/utils/adt/dbsize.c
@@ -256,14 +256,14 @@ pg_tablespace_size_name(PG_FUNCTION_ARGS)
  * calculate size of (one fork of) a relation
  */
 static int64
-calculate_relation_size(RelFileNode *rfn, ForkNumber forknum)
+calculate_relation_size(RelFileNode *rfn, BackendId backend, ForkNumber forknum)
 {
 	int64		totalsize = 0;
 	char	   *relationpath;
 	char		pathname[MAXPGPATH];
 	unsigned int segcount = 0;
 
-	relationpath = relpath(*rfn, forknum);
+	relationpath = relpathbackend(*rfn, backend, forknum);
 
 	for (segcount = 0;; segcount++)
 	{
@@ -303,7 +303,7 @@ pg_relation_size(PG_FUNCTION_ARGS)
 
 	rel = relation_open(relOid, AccessShareLock);
 
-	size = calculate_relation_size(&(rel->rd_node),
+	size = calculate_relation_size(&(rel->rd_node), rel->rd_backend,
 							  forkname_to_number(text_to_cstring(forkName)));
 
 	relation_close(rel, AccessShareLock);
@@ -327,12 +327,14 @@ calculate_toast_table_size(Oid toastrelid)
 
 	/* toast heap size, including FSM and VM size */
 	for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
-		size += calculate_relation_size(&(toastRel->rd_node), forkNum);
+		size += calculate_relation_size(&(toastRel->rd_node),
+										toastRel->rd_backend, forkNum);
 
 	/* toast index size, including FSM and VM size */
 	toastIdxRel = relation_open(toastRel->rd_rel->reltoastidxid, AccessShareLock);
 	for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
-		size += calculate_relation_size(&(toastIdxRel->rd_node), forkNum);
+		size += calculate_relation_size(&(toastIdxRel->rd_node),
+										toastIdxRel->rd_backend, forkNum);
 
 	relation_close(toastIdxRel, AccessShareLock);
 	relation_close(toastRel, AccessShareLock);
@@ -361,7 +363,8 @@ calculate_table_size(Oid relOid)
 	 * heap size, including FSM and VM
 	 */
 	for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
-		size += calculate_relation_size(&(rel->rd_node), forkNum);
+		size += calculate_relation_size(&(rel->rd_node), rel->rd_backend,
+										forkNum);
 
 	/*
 	 * Size of toast relation
@@ -404,7 +407,9 @@ calculate_indexes_size(Oid relOid)
 			idxRel = relation_open(idxOid, AccessShareLock);
 
 			for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
-				size += calculate_relation_size(&(idxRel->rd_node), forkNum);
+				size += calculate_relation_size(&(idxRel->rd_node),
+												idxRel->rd_backend,
+												forkNum);
 
 			relation_close(idxRel, AccessShareLock);
 		}
@@ -575,6 +580,7 @@ pg_relation_filepath(PG_FUNCTION_ARGS)
 	HeapTuple	tuple;
 	Form_pg_class relform;
 	RelFileNode rnode;
+	BackendId	backend;
 	char	   *path;
 
 	tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
@@ -612,12 +618,27 @@ pg_relation_filepath(PG_FUNCTION_ARGS)
 			break;
 	}
 
-	ReleaseSysCache(tuple);
-
 	if (!OidIsValid(rnode.relNode))
+	{
+		ReleaseSysCache(tuple);
 		PG_RETURN_NULL();
+	}
+
+	/* If temporary, determine owning backend. */
+	if (!relform->relistemp)
+		backend = InvalidBackendId;
+	else if (isTempOrToastNamespace(relform->relnamespace))
+		backend = MyBackendId;
+	else
+	{
+		/* Do it the hard way. */
+		backend = GetTempNamespaceBackendId(relform->relnamespace);
+		Assert(backend != InvalidOid);
+	}
+
+	ReleaseSysCache(tuple);
 
-	path = relpath(rnode, MAIN_FORKNUM);
+	path = relpathbackend(rnode, backend, MAIN_FORKNUM);
 
 	PG_RETURN_TEXT_P(cstring_to_text(path));
 }
diff --git a/src/backend/utils/cache/inval.c b/src/backend/utils/cache/inval.c
index 3b15d85..91de76d 100644
--- a/src/backend/utils/cache/inval.c
+++ b/src/backend/utils/cache/inval.c
@@ -1165,7 +1165,7 @@ CacheInvalidateRelcacheByRelid(Oid relid)
  * replaying WAL as well as when creating it.
  */
 void
-CacheInvalidateSmgr(RelFileNode rnode)
+CacheInvalidateSmgr(BackendRelFileNode rnode)
 {
 	SharedInvalidationMessage msg;
 
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index dda69e8..bc355ca 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -858,10 +858,20 @@ RelationBuildDesc(Oid targetRelId, bool insertIt)
 	relation->rd_createSubid = InvalidSubTransactionId;
 	relation->rd_newRelfilenodeSubid = InvalidSubTransactionId;
 	relation->rd_istemp = relation->rd_rel->relistemp;
-	if (relation->rd_istemp)
-		relation->rd_islocaltemp = isTempOrToastNamespace(relation->rd_rel->relnamespace);
+	if (!relation->rd_istemp)
+		relation->rd_backend = InvalidBackendId;
+	else if (isTempOrToastNamespace(relation->rd_rel->relnamespace))
+		relation->rd_backend = MyBackendId;
 	else
-		relation->rd_islocaltemp = false;
+	{
+		/*
+		 * If it's a temporary table, but not one of ours, we have to use
+		 * the slow, grotty method to figure out the owning backend.
+		 */
+		relation->rd_backend =
+			GetTempNamespaceBackendId(relation->rd_rel->relnamespace);
+		Assert(relation->rd_backend != InvalidOid);
+	}
 
 	/*
 	 * initialize the tuple descriptor (relation->rd_att).
@@ -1424,7 +1434,7 @@ formrdesc(const char *relationName, Oid relationReltype,
 	relation->rd_createSubid = InvalidSubTransactionId;
 	relation->rd_newRelfilenodeSubid = InvalidSubTransactionId;
 	relation->rd_istemp = false;
-	relation->rd_islocaltemp = false;
+	relation->rd_backend = InvalidBackendId;
 
 	/*
 	 * initialize relation tuple form
@@ -2515,7 +2525,7 @@ RelationBuildLocalRelation(const char *relname,
 
 	/* it is temporary if and only if it is in my temp-table namespace */
 	rel->rd_istemp = isTempOrToastNamespace(relnamespace);
-	rel->rd_islocaltemp = rel->rd_istemp;
+	rel->rd_backend = rel->rd_istemp ? MyBackendId : InvalidBackendId;
 
 	/*
 	 * create a new tuple descriptor from the one passed in.  We do this
@@ -2629,7 +2639,7 @@ void
 RelationSetNewRelfilenode(Relation relation, TransactionId freezeXid)
 {
 	Oid			newrelfilenode;
-	RelFileNode newrnode;
+	BackendRelFileNode newrnode;
 	Relation	pg_class;
 	HeapTuple	tuple;
 	Form_pg_class classform;
@@ -2640,7 +2650,8 @@ RelationSetNewRelfilenode(Relation relation, TransactionId freezeXid)
 		   TransactionIdIsNormal(freezeXid));
 
 	/* Allocate a new relfilenode */
-	newrelfilenode = GetNewRelFileNode(relation->rd_rel->reltablespace, NULL);
+	newrelfilenode = GetNewRelFileNode(relation->rd_rel->reltablespace, NULL,
+									   relation->rd_backend);
 
 	/*
 	 * Get a writable copy of the pg_class tuple for the given relation.
@@ -2660,9 +2671,10 @@ RelationSetNewRelfilenode(Relation relation, TransactionId freezeXid)
 	 * NOTE: any conflict in relfilenode value will be caught here, if
 	 * GetNewRelFileNode messes up for any reason.
 	 */
-	newrnode = relation->rd_node;
-	newrnode.relNode = newrelfilenode;
-	RelationCreateStorage(newrnode, relation->rd_istemp);
+	newrnode.node = relation->rd_node;
+	newrnode.node.relNode = newrelfilenode;
+	newrnode.backend = relation->rd_backend;
+	RelationCreateStorage(newrnode.node, relation->rd_istemp);
 	smgrclosenode(newrnode);
 
 	/*
diff --git a/src/backend/utils/probes.d b/src/backend/utils/probes.d
index 8ccb948..b06f8ff 100644
--- a/src/backend/utils/probes.d
+++ b/src/backend/utils/probes.d
@@ -55,7 +55,7 @@ provider postgresql {
 	probe sort__done(bool, long);
 
 	probe buffer__read__start(ForkNumber, BlockNumber, Oid, Oid, Oid, bool, bool);
-	probe buffer__read__done(ForkNumber, BlockNumber, Oid, Oid, Oid, bool, bool, bool);
+	probe buffer__read__done(ForkNumber, BlockNumber, Oid, Oid, Oid, int, bool, bool);
 	probe buffer__flush__start(ForkNumber, BlockNumber, Oid, Oid, Oid);
 	probe buffer__flush__done(ForkNumber, BlockNumber, Oid, Oid, Oid);
 
@@ -81,10 +81,10 @@ provider postgresql {
 	probe twophase__checkpoint__start();
 	probe twophase__checkpoint__done();
 
-	probe smgr__md__read__start(ForkNumber, BlockNumber, Oid, Oid, Oid);
-	probe smgr__md__read__done(ForkNumber, BlockNumber, Oid, Oid, Oid, int, int);
-	probe smgr__md__write__start(ForkNumber, BlockNumber, Oid, Oid, Oid);
-	probe smgr__md__write__done(ForkNumber, BlockNumber, Oid, Oid, Oid, int, int);
+	probe smgr__md__read__start(ForkNumber, BlockNumber, Oid, Oid, Oid, int);
+	probe smgr__md__read__done(ForkNumber, BlockNumber, Oid, Oid, Oid, int, int, int);
+	probe smgr__md__write__start(ForkNumber, BlockNumber, Oid, Oid, Oid, int);
+	probe smgr__md__write__done(ForkNumber, BlockNumber, Oid, Oid, Oid, int, int, int);
 
 	probe xlog__insert(unsigned char, unsigned char);
 	probe xlog__switch();
diff --git a/src/include/catalog/catalog.h b/src/include/catalog/catalog.h
index bd430cb..765f571 100644
--- a/src/include/catalog/catalog.h
+++ b/src/include/catalog/catalog.h
@@ -25,10 +25,17 @@
 
 extern const char *forkNames[];
 extern ForkNumber forkname_to_number(char *forkName);
+extern int forkname_chars(const char *str);
 
-extern char *relpath(RelFileNode rnode, ForkNumber forknum);
+extern char *relpathbackend(RelFileNode rnode, BackendId backend,
+			  ForkNumber forknum);
 extern char *GetDatabasePath(Oid dbNode, Oid spcNode);
 
+#define relpath(rnode, forknum) \
+		relpathbackend((rnode).node, (rnode).backend, (forknum))
+#define relpathperm(rnode, forknum) \
+		relpathbackend((rnode), InvalidBackendId, (forknum))
+
 extern bool IsSystemRelation(Relation relation);
 extern bool IsToastRelation(Relation relation);
 
@@ -45,6 +52,7 @@ extern bool IsSharedRelation(Oid relationId);
 extern Oid	GetNewOid(Relation relation);
 extern Oid GetNewOidWithIndex(Relation relation, Oid indexId,
 				   AttrNumber oidcolumn);
-extern Oid	GetNewRelFileNode(Oid reltablespace, Relation pg_class);
+extern Oid	GetNewRelFileNode(Oid reltablespace, Relation pg_class,
+				  BackendId backend);
 
 #endif   /* CATALOG_H */
diff --git a/src/include/catalog/storage.h b/src/include/catalog/storage.h
index 609f1c6..7712d1f 100644
--- a/src/include/catalog/storage.h
+++ b/src/include/catalog/storage.h
@@ -30,8 +30,7 @@ extern void RelationTruncate(Relation rel, BlockNumber nblocks);
  * naming
  */
 extern void smgrDoPendingDeletes(bool isCommit);
-extern int smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr,
-					  bool *haveNonTemp);
+extern int smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr);
 extern void AtSubCommit_smgr(void);
 extern void AtSubAbort_smgr(void);
 extern void PostPrepare_smgr(void);
diff --git a/src/include/postmaster/bgwriter.h b/src/include/postmaster/bgwriter.h
index 06a4e37..a22fbee 100644
--- a/src/include/postmaster/bgwriter.h
+++ b/src/include/postmaster/bgwriter.h
@@ -27,7 +27,7 @@ extern void BackgroundWriterMain(void);
 extern void RequestCheckpoint(int flags);
 extern void CheckpointWriteDelay(int flags, double progress);
 
-extern bool ForwardFsyncRequest(RelFileNode rnode, ForkNumber forknum,
+extern bool ForwardFsyncRequest(BackendRelFileNode rnode, ForkNumber forknum,
 					BlockNumber segno);
 extern void AbsorbFsyncRequests(void);
 
diff --git a/src/include/storage/bufmgr.h b/src/include/storage/bufmgr.h
index f38f545..d4bf341 100644
--- a/src/include/storage/bufmgr.h
+++ b/src/include/storage/bufmgr.h
@@ -160,7 +160,7 @@ extern Buffer ReadBuffer(Relation reln, BlockNumber blockNum);
 extern Buffer ReadBufferExtended(Relation reln, ForkNumber forkNum,
 				   BlockNumber blockNum, ReadBufferMode mode,
 				   BufferAccessStrategy strategy);
-extern Buffer ReadBufferWithoutRelcache(RelFileNode rnode, bool isTemp,
+extern Buffer ReadBufferWithoutRelcache(RelFileNode rnode,
 						  ForkNumber forkNum, BlockNumber blockNum,
 						  ReadBufferMode mode, BufferAccessStrategy strategy);
 extern void ReleaseBuffer(Buffer buffer);
@@ -180,8 +180,8 @@ extern BlockNumber BufferGetBlockNumber(Buffer buffer);
 extern BlockNumber RelationGetNumberOfBlocks(Relation relation);
 extern void FlushRelationBuffers(Relation rel);
 extern void FlushDatabaseBuffers(Oid dbid);
-extern void DropRelFileNodeBuffers(RelFileNode rnode, ForkNumber forkNum,
-					   bool istemp, BlockNumber firstDelBlock);
+extern void DropRelFileNodeBuffers(BackendRelFileNode rnode,
+					   ForkNumber forkNum, BlockNumber firstDelBlock);
 extern void DropDatabaseBuffers(Oid dbid);
 
 #ifdef NOT_USED
diff --git a/src/include/storage/relfilenode.h b/src/include/storage/relfilenode.h
index 6f0c0ad..9bb0fa2 100644
--- a/src/include/storage/relfilenode.h
+++ b/src/include/storage/relfilenode.h
@@ -14,6 +14,8 @@
 #ifndef RELFILENODE_H
 #define RELFILENODE_H
 
+#include "storage/backendid.h"
+
 /*
  * The physical storage of a relation consists of one or more forks. The
  * main fork is always created, but in addition to that there can be
@@ -37,7 +39,8 @@ typedef enum ForkNumber
 
 /*
  * RelFileNode must provide all that we need to know to physically access
- * a relation. Note, however, that a "physical" relation is comprised of
+ * a relation, with the exception of the backend ID, which can be provided
+ * separately. Note, however, that a "physical" relation is comprised of
  * multiple files on the filesystem, as each fork is stored as a separate
  * file, and each fork can be divided into multiple segments. See md.c.
  *
@@ -74,14 +77,30 @@ typedef struct RelFileNode
 } RelFileNode;
 
 /*
- * Note: RelFileNodeEquals compares relNode first since that is most likely
- * to be different in two unequal RelFileNodes.  It is probably redundant
- * to compare spcNode if the other two fields are found equal, but do it
- * anyway to be sure.
+ * Augmenting a relfilenode with the backend ID provides all the information
+ * we need to locate the physical storage.
+ */
+typedef struct BackendRelFileNode
+{
+	RelFileNode	node;
+	BackendId	backend;
+} BackendRelFileNode;
+
+/*
+ * Note: RelFileNodeEquals and BackendRelFileNodeEquals compare relNode first
+ * since that is most likely to be different in two unequal RelFileNodes.  It
+ * is probably redundant to compare spcNode if the other fields are found equal,
+ * but do it anyway to be sure.
  */
 #define RelFileNodeEquals(node1, node2) \
 	((node1).relNode == (node2).relNode && \
 	 (node1).dbNode == (node2).dbNode && \
 	 (node1).spcNode == (node2).spcNode)
 
+#define BackendRelFileNodeEquals(node1, node2) \
+	((node1).node.relNode == (node2).node.relNode && \
+	 (node1).node.dbNode == (node2).node.dbNode && \
+	 (node1).backend == (node2).backend && \
+	 (node1).node.spcNode == (node2).node.spcNode)
+
 #endif   /* RELFILENODE_H */
diff --git a/src/include/storage/sinval.h b/src/include/storage/sinval.h
index bbdde81..0168d17 100644
--- a/src/include/storage/sinval.h
+++ b/src/include/storage/sinval.h
@@ -92,7 +92,7 @@ typedef struct
 typedef struct
 {
 	int16		id;				/* type field --- must be first */
-	RelFileNode rnode;			/* physical file ID */
+	BackendRelFileNode rnode;	/* physical file ID */
 } SharedInvalSmgrMsg;
 
 #define SHAREDINVALRELMAP_ID	(-4)
diff --git a/src/include/storage/smgr.h b/src/include/storage/smgr.h
index cf248b8..7ae78ec 100644
--- a/src/include/storage/smgr.h
+++ b/src/include/storage/smgr.h
@@ -16,6 +16,7 @@
 
 #include "access/xlog.h"
 #include "fmgr.h"
+#include "storage/backendid.h"
 #include "storage/block.h"
 #include "storage/relfilenode.h"
 
@@ -38,7 +39,7 @@
 typedef struct SMgrRelationData
 {
 	/* rnode is the hashtable lookup key, so it must be first! */
-	RelFileNode smgr_rnode;		/* relation physical identifier */
+	BackendRelFileNode smgr_rnode;		/* relation physical identifier */
 
 	/* pointer to owning pointer, or NULL if none */
 	struct SMgrRelationData **smgr_owner;
@@ -68,28 +69,30 @@ typedef struct SMgrRelationData
 
 typedef SMgrRelationData *SMgrRelation;
 
+#define SmgrIsTemp(smgr) \
+	((smgr)->smgr_rnode.backend != InvalidBackendId)
 
 extern void smgrinit(void);
-extern SMgrRelation smgropen(RelFileNode rnode);
+extern SMgrRelation smgropen(RelFileNode rnode, BackendId backend);
 extern bool smgrexists(SMgrRelation reln, ForkNumber forknum);
 extern void smgrsetowner(SMgrRelation *owner, SMgrRelation reln);
 extern void smgrclose(SMgrRelation reln);
 extern void smgrcloseall(void);
-extern void smgrclosenode(RelFileNode rnode);
+extern void smgrclosenode(BackendRelFileNode rnode);
 extern void smgrcreate(SMgrRelation reln, ForkNumber forknum, bool isRedo);
 extern void smgrdounlink(SMgrRelation reln, ForkNumber forknum,
-			 bool isTemp, bool isRedo);
+			 bool isRedo);
 extern void smgrextend(SMgrRelation reln, ForkNumber forknum,
-		   BlockNumber blocknum, char *buffer, bool isTemp);
+		   BlockNumber blocknum, char *buffer, bool skipFsync);
 extern void smgrprefetch(SMgrRelation reln, ForkNumber forknum,
 			 BlockNumber blocknum);
 extern void smgrread(SMgrRelation reln, ForkNumber forknum,
 		 BlockNumber blocknum, char *buffer);
 extern void smgrwrite(SMgrRelation reln, ForkNumber forknum,
-		  BlockNumber blocknum, char *buffer, bool isTemp);
+		  BlockNumber blocknum, char *buffer, bool skipFsync);
 extern BlockNumber smgrnblocks(SMgrRelation reln, ForkNumber forknum);
 extern void smgrtruncate(SMgrRelation reln, ForkNumber forknum,
-			 BlockNumber nblocks, bool isTemp);
+			 BlockNumber nblocks);
 extern void smgrimmedsync(SMgrRelation reln, ForkNumber forknum);
 extern void smgrpreckpt(void);
 extern void smgrsync(void);
@@ -103,27 +106,28 @@ extern void mdinit(void);
 extern void mdclose(SMgrRelation reln, ForkNumber forknum);
 extern void mdcreate(SMgrRelation reln, ForkNumber forknum, bool isRedo);
 extern bool mdexists(SMgrRelation reln, ForkNumber forknum);
-extern void mdunlink(RelFileNode rnode, ForkNumber forknum, bool isRedo);
+extern void mdunlink(BackendRelFileNode rnode, ForkNumber forknum, bool isRedo);
 extern void mdextend(SMgrRelation reln, ForkNumber forknum,
-		 BlockNumber blocknum, char *buffer, bool isTemp);
+		 BlockNumber blocknum, char *buffer, bool skipFsync);
 extern void mdprefetch(SMgrRelation reln, ForkNumber forknum,
 		   BlockNumber blocknum);
 extern void mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 	   char *buffer);
 extern void mdwrite(SMgrRelation reln, ForkNumber forknum,
-		BlockNumber blocknum, char *buffer, bool isTemp);
+		BlockNumber blocknum, char *buffer, bool skipFsync);
 extern BlockNumber mdnblocks(SMgrRelation reln, ForkNumber forknum);
 extern void mdtruncate(SMgrRelation reln, ForkNumber forknum,
-		   BlockNumber nblocks, bool isTemp);
+		   BlockNumber nblocks);
 extern void mdimmedsync(SMgrRelation reln, ForkNumber forknum);
 extern void mdpreckpt(void);
 extern void mdsync(void);
 extern void mdpostckpt(void);
 
 extern void SetForwardFsyncRequests(void);
-extern void RememberFsyncRequest(RelFileNode rnode, ForkNumber forknum,
+extern void RememberFsyncRequest(BackendRelFileNode rnode, ForkNumber forknum,
 					 BlockNumber segno);
-extern void ForgetRelationFsyncRequests(RelFileNode rnode, ForkNumber forknum);
+extern void ForgetRelationFsyncRequests(BackendRelFileNode rnode,
+							ForkNumber forknum);
 extern void ForgetDatabaseFsyncRequests(Oid dbid);
 
 /* smgrtype.c */
diff --git a/src/include/utils/inval.h b/src/include/utils/inval.h
index a86a17c..7fab919 100644
--- a/src/include/utils/inval.h
+++ b/src/include/utils/inval.h
@@ -49,7 +49,7 @@ extern void CacheInvalidateRelcacheByTuple(HeapTuple classTuple);
 
 extern void CacheInvalidateRelcacheByRelid(Oid relid);
 
-extern void CacheInvalidateSmgr(RelFileNode rnode);
+extern void CacheInvalidateSmgr(BackendRelFileNode rnode);
 
 extern void CacheInvalidateRelmap(Oid databaseId);
 
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 444e892..296c651 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -127,7 +127,7 @@ typedef struct RelationData
 	struct SMgrRelationData *rd_smgr;	/* cached file handle, or NULL */
 	int			rd_refcnt;		/* reference count */
 	bool		rd_istemp;		/* rel is a temporary relation */
-	bool		rd_islocaltemp; /* rel is a temp rel of this session */
+	BackendId	rd_backend;		/* owning backend id, if temporary relation */
 	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 =
@@ -347,7 +347,7 @@ typedef struct StdRdOptions
 #define RelationOpenSmgr(relation) \
 	do { \
 		if ((relation)->rd_smgr == NULL) \
-			smgrsetowner(&((relation)->rd_smgr), smgropen((relation)->rd_node)); \
+			smgrsetowner(&((relation)->rd_smgr), smgropen((relation)->rd_node, (relation)->rd_backend)); \
 	} while (0)
 
 /*
@@ -393,7 +393,7 @@ typedef struct StdRdOptions
  * Beware of multiple eval of argument
  */
 #define RELATION_IS_LOCAL(relation) \
-	((relation)->rd_islocaltemp || \
+	((relation)->rd_backend == MyBackendId || \
 	 (relation)->rd_createSubid != InvalidSubTransactionId)
 
 /*
@@ -403,7 +403,7 @@ typedef struct StdRdOptions
  * Beware of multiple eval of argument
  */
 #define RELATION_IS_OTHER_TEMP(relation) \
-	((relation)->rd_istemp && !(relation)->rd_islocaltemp)
+	((relation)->rd_istemp && (relation)->rd_backend != MyBackendId)
 
 /* routines in utils/cache/relcache.c */
 extern void RelationIncrementReferenceCount(Relation rel);

diff --git a/src/backend/access/heap/visibilitymap.c b/src/backend/access/heap/visibilitymap.c
index d1f7bcc..9645c95 100644
--- a/src/backend/access/heap/visibilitymap.c
+++ b/src/backend/access/heap/visibilitymap.c
@@ -373,8 +373,7 @@ visibilitymap_truncate(Relation rel, BlockNumber nheapblocks)
 	}
 
 	/* Truncate the unused VM pages, and send smgr inval message */
-	smgrtruncate(rel->rd_smgr, VISIBILITYMAP_FORKNUM, newnblocks,
-				 rel->rd_istemp);
+	smgrtruncate(rel->rd_smgr, VISIBILITYMAP_FORKNUM, newnblocks);
 
 	/*
 	 * We might as well update the local smgr_vm_nblocks setting. smgrtruncate
diff --git a/src/backend/access/nbtree/nbtsort.c b/src/backend/access/nbtree/nbtsort.c
index 89ed8a0..06e304e 100644
--- a/src/backend/access/nbtree/nbtsort.c
+++ b/src/backend/access/nbtree/nbtsort.c
@@ -295,9 +295,8 @@ _bt_blwritepage(BTWriteState *wstate, Page page, BlockNumber blkno)
 	}
 
 	/*
-	 * Now write the page.	We say isTemp = true even if it's not a temp
-	 * index, because there's no need for smgr to schedule an fsync for this
-	 * write; we'll do it ourselves before ending the build.
+	 * Now write the page.	There's no need for smgr to schedule an fsync for
+	 * this write; we'll do it ourselves before ending the build.
 	 */
 	if (blkno == wstate->btws_pages_written)
 	{
diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c
index d0680f0..615a7fa 100644
--- a/src/backend/access/transam/twophase.c
+++ b/src/backend/access/transam/twophase.c
@@ -865,8 +865,8 @@ StartPrepare(GlobalTransaction gxact)
 	hdr.prepared_at = gxact->prepared_at;
 	hdr.owner = gxact->owner;
 	hdr.nsubxacts = xactGetCommittedChildren(&children);
-	hdr.ncommitrels = smgrGetPendingDeletes(true, &commitrels, NULL);
-	hdr.nabortrels = smgrGetPendingDeletes(false, &abortrels, NULL);
+	hdr.ncommitrels = smgrGetPendingDeletes(true, &commitrels);
+	hdr.nabortrels = smgrGetPendingDeletes(false, &abortrels);
 	hdr.ninvalmsgs = xactGetCommittedInvalidationMessages(&invalmsgs,
 														  &hdr.initfileinval);
 	StrNCpy(hdr.gid, gxact->gid, GIDSIZE);
@@ -1320,13 +1320,13 @@ FinishPreparedTransaction(const char *gid, bool isCommit)
 	}
 	for (i = 0; i < ndelrels; i++)
 	{
-		SMgrRelation srel = smgropen(delrels[i]);
+		SMgrRelation srel = smgropen(delrels[i], InvalidBackendId);
 		ForkNumber	fork;
 
 		for (fork = 0; fork <= MAX_FORKNUM; fork++)
 		{
 			if (smgrexists(srel, fork))
-				smgrdounlink(srel, fork, false, false);
+				smgrdounlink(srel, fork, false);
 		}
 		smgrclose(srel);
 	}
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 60e22d0..7836677 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -912,7 +912,6 @@ RecordTransactionCommit(void)
 	TransactionId latestXid = InvalidTransactionId;
 	int			nrels;
 	RelFileNode *rels;
-	bool		haveNonTemp;
 	int			nchildren;
 	TransactionId *children;
 	int			nmsgs;
@@ -920,7 +919,7 @@ RecordTransactionCommit(void)
 	bool		RelcacheInitFileInval;
 
 	/* Get data needed for commit record */
-	nrels = smgrGetPendingDeletes(true, &rels, &haveNonTemp);
+	nrels = smgrGetPendingDeletes(true, &rels);
 	nchildren = xactGetCommittedChildren(&children);
 	nmsgs = xactGetCommittedInvalidationMessages(&invalMessages,
 												 &RelcacheInitFileInval);
@@ -1047,7 +1046,7 @@ 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:
@@ -1333,7 +1332,7 @@ 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? */
@@ -4473,7 +4472,7 @@ 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++)
@@ -4481,7 +4480,7 @@ 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);
@@ -4578,7 +4577,7 @@ 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++)
@@ -4586,7 +4585,7 @@ 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);
@@ -4660,7 +4659,7 @@ 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);
@@ -4715,7 +4714,7 @@ 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);
diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c
index b5bbc5e..dba842c 100644
--- a/src/backend/access/transam/xlogutils.c
+++ b/src/backend/access/transam/xlogutils.c
@@ -68,7 +68,7 @@ log_invalid_page(RelFileNode node, ForkNumber forkno, BlockNumber blkno,
 	 */
 	if (log_min_messages <= DEBUG1 || client_min_messages <= DEBUG1)
 	{
-		char	   *path = relpath(node, forkno);
+		char	   *path = relpathperm(node, forkno);
 
 		if (present)
 			elog(DEBUG1, "page %u of relation %s is uninitialized",
@@ -133,7 +133,7 @@ forget_invalid_pages(RelFileNode node, ForkNumber forkno, BlockNumber minblkno)
 		{
 			if (log_min_messages <= DEBUG2 || client_min_messages <= DEBUG2)
 			{
-				char	   *path = relpath(hentry->key.node, forkno);
+				char	   *path = relpathperm(hentry->key.node, forkno);
 
 				elog(DEBUG2, "page %u of relation %s has been dropped",
 					 hentry->key.blkno, path);
@@ -166,7 +166,7 @@ forget_invalid_pages_db(Oid dbid)
 		{
 			if (log_min_messages <= DEBUG2 || client_min_messages <= DEBUG2)
 			{
-				char	   *path = relpath(hentry->key.node, hentry->key.forkno);
+				char	   *path = relpathperm(hentry->key.node, hentry->key.forkno);
 
 				elog(DEBUG2, "page %u of relation %s has been dropped",
 					 hentry->key.blkno, path);
@@ -200,7 +200,7 @@ XLogCheckInvalidPages(void)
 	 */
 	while ((hentry = (xl_invalid_page *) hash_seq_search(&status)) != NULL)
 	{
-		char	   *path = relpath(hentry->key.node, hentry->key.forkno);
+		char	   *path = relpathperm(hentry->key.node, hentry->key.forkno);
 
 		if (hentry->present)
 			elog(WARNING, "page %u of relation %s was uninitialized",
@@ -276,7 +276,7 @@ XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
 	Assert(blkno != P_NEW);
 
 	/* Open the relation at smgr level */
-	smgr = smgropen(rnode);
+	smgr = smgropen(rnode, InvalidBackendId);
 
 	/*
 	 * Create the target file if it doesn't already exist.  This lets us cope
@@ -293,7 +293,7 @@ XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
 	if (blkno < lastblock)
 	{
 		/* page exists in file */
-		buffer = ReadBufferWithoutRelcache(rnode, false, forknum, blkno,
+		buffer = ReadBufferWithoutRelcache(rnode, forknum, blkno,
 										   mode, NULL);
 	}
 	else
@@ -312,7 +312,7 @@ XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
 		{
 			if (buffer != InvalidBuffer)
 				ReleaseBuffer(buffer);
-			buffer = ReadBufferWithoutRelcache(rnode, false, forknum,
+			buffer = ReadBufferWithoutRelcache(rnode, forknum,
 											   P_NEW, mode, NULL);
 			lastblock++;
 		}
diff --git a/src/backend/catalog/catalog.c b/src/backend/catalog/catalog.c
index 3edfc23..5ec5602 100644
--- a/src/backend/catalog/catalog.c
+++ b/src/backend/catalog/catalog.c
@@ -78,12 +78,37 @@ forkname_to_number(char *forkName)
 }
 
 /*
- * relpath			- construct path to a relation's file
+ * forkname_chars
+ * 		We use this to figure out whether a filename could be a relation
+ * 		fork (as opposed to an oddly named stray file that somehow ended
+ * 		up in the database directory).  If the passed string begins with
+ * 		a fork name (other than the main fork name), we return its length.
+ * 		If not, we return 0.
+ *
+ * Note that the present coding assumes that there are no fork names which
+ * are prefixes of other fork names.
+ */
+int
+forkname_chars(const char *str)
+{
+	ForkNumber	forkNum;
+
+	for (forkNum = 1; forkNum <= MAX_FORKNUM; forkNum++)
+	{
+		int len = strlen(forkNames[forkNum]);
+		if (strncmp(forkNames[forkNum], str, len) == 0)
+			return len;
+	}
+	return 0;
+}
+
+/*
+ * relpathbackend - construct path to a relation's file
  *
  * Result is a palloc'd string.
  */
 char *
-relpath(RelFileNode rnode, ForkNumber forknum)
+relpathbackend(RelFileNode rnode, BackendId backend, ForkNumber forknum)
 {
 	int			pathlen;
 	char	   *path;
@@ -92,6 +117,7 @@ relpath(RelFileNode rnode, ForkNumber forknum)
 	{
 		/* Shared system relations live in {datadir}/global */
 		Assert(rnode.dbNode == 0);
+		Assert(backend == InvalidBackendId);
 		pathlen = 7 + OIDCHARS + 1 + FORKNAMECHARS + 1;
 		path = (char *) palloc(pathlen);
 		if (forknum != MAIN_FORKNUM)
@@ -103,29 +129,69 @@ relpath(RelFileNode rnode, ForkNumber forknum)
 	else if (rnode.spcNode == DEFAULTTABLESPACE_OID)
 	{
 		/* The default tablespace is {datadir}/base */
-		pathlen = 5 + OIDCHARS + 1 + OIDCHARS + 1 + FORKNAMECHARS + 1;
-		path = (char *) palloc(pathlen);
-		if (forknum != MAIN_FORKNUM)
-			snprintf(path, pathlen, "base/%u/%u_%s",
-					 rnode.dbNode, rnode.relNode, forkNames[forknum]);
+		if (backend == InvalidBackendId)
+		{
+			pathlen = 5 + OIDCHARS + 1 + OIDCHARS + 1 + FORKNAMECHARS + 1;
+			path = (char *) palloc(pathlen);
+			if (forknum != MAIN_FORKNUM)
+				snprintf(path, pathlen, "base/%u/%u_%s",
+						 rnode.dbNode, rnode.relNode,
+						 forkNames[forknum]);
+			else
+				snprintf(path, pathlen, "base/%u/%u",
+						 rnode.dbNode, rnode.relNode);
+		}
 		else
-			snprintf(path, pathlen, "base/%u/%u",
-					 rnode.dbNode, rnode.relNode);
+		{
+			/* OIDCHARS will suffice for an integer, too */
+			pathlen = 5 + OIDCHARS + 2 + OIDCHARS + 1 + OIDCHARS + 1
+					+ FORKNAMECHARS + 1;
+			path = (char *) palloc(pathlen);
+			if (forknum != MAIN_FORKNUM)
+				snprintf(path, pathlen, "base/%u/t%d_%u_%s",
+						 rnode.dbNode, backend, rnode.relNode,
+						 forkNames[forknum]);
+			else
+				snprintf(path, pathlen, "base/%u/t%d_%u",
+						 rnode.dbNode, backend, rnode.relNode);
+		}
 	}
 	else
 	{
 		/* All other tablespaces are accessed via symlinks */
-		pathlen = 9 + 1 + OIDCHARS + 1 + strlen(TABLESPACE_VERSION_DIRECTORY) +
-			1 + OIDCHARS + 1 + OIDCHARS + 1 + FORKNAMECHARS + 1;
-		path = (char *) palloc(pathlen);
-		if (forknum != MAIN_FORKNUM)
-			snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/%u_%s",
-					 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
-					 rnode.dbNode, rnode.relNode, forkNames[forknum]);
+		if (backend == InvalidBackendId)
+		{
+			pathlen = 9 + 1 + OIDCHARS + 1
+					+ strlen(TABLESPACE_VERSION_DIRECTORY) + 1 + OIDCHARS + 1
+					+ OIDCHARS + 1 + FORKNAMECHARS + 1;
+			path = (char *) palloc(pathlen);
+			if (forknum != MAIN_FORKNUM)
+				snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/%u_%s",
+						 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
+						 rnode.dbNode, rnode.relNode,
+						 forkNames[forknum]);
+			else
+				snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/%u",
+						 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
+						 rnode.dbNode, rnode.relNode);
+		}
 		else
-			snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/%u",
-					 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
-					 rnode.dbNode, rnode.relNode);
+		{
+			/* OIDCHARS will suffice for an integer, too */
+			pathlen = 9 + 1 + OIDCHARS + 1
+					+ strlen(TABLESPACE_VERSION_DIRECTORY) + 1 + OIDCHARS + 2
+					+ OIDCHARS + 1 + OIDCHARS + 1 + FORKNAMECHARS + 1;
+			path = (char *) palloc(pathlen);
+			if (forknum != MAIN_FORKNUM)
+				snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/t%d_%u_%s",
+						 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
+						 rnode.dbNode, backend, rnode.relNode,
+						 forkNames[forknum]);
+			else
+				snprintf(path, pathlen, "pg_tblspc/%u/%s/%u/t%d_%u",
+						 rnode.spcNode, TABLESPACE_VERSION_DIRECTORY,
+						 rnode.dbNode, backend, rnode.relNode);
+		}
 	}
 	return path;
 }
@@ -458,16 +524,17 @@ GetNewOidWithIndex(Relation relation, Oid indexId, AttrNumber oidcolumn)
  * created by bootstrap have preassigned OIDs, so there's no need.
  */
 Oid
-GetNewRelFileNode(Oid reltablespace, Relation pg_class)
+GetNewRelFileNode(Oid reltablespace, Relation pg_class, BackendId backend)
 {
-	RelFileNode rnode;
+	BackendRelFileNode rnode;
 	char	   *rpath;
 	int			fd;
 	bool		collides;
 
 	/* This logic should match RelationInitPhysicalAddr */
-	rnode.spcNode = reltablespace ? reltablespace : MyDatabaseTableSpace;
-	rnode.dbNode = (rnode.spcNode == GLOBALTABLESPACE_OID) ? InvalidOid : MyDatabaseId;
+	rnode.node.spcNode = reltablespace ? reltablespace : MyDatabaseTableSpace;
+	rnode.node.dbNode = (rnode.node.spcNode == GLOBALTABLESPACE_OID) ? InvalidOid : MyDatabaseId;
+	rnode.backend = backend;
 
 	do
 	{
@@ -475,9 +542,9 @@ GetNewRelFileNode(Oid reltablespace, Relation pg_class)
 
 		/* Generate the OID */
 		if (pg_class)
-			rnode.relNode = GetNewOid(pg_class);
+			rnode.node.relNode = GetNewOid(pg_class);
 		else
-			rnode.relNode = GetNewObjectId();
+			rnode.node.relNode = GetNewObjectId();
 
 		/* Check for existing file of same name */
 		rpath = relpath(rnode, MAIN_FORKNUM);
@@ -508,5 +575,5 @@ GetNewRelFileNode(Oid reltablespace, Relation pg_class)
 		pfree(rpath);
 	} while (collides);
 
-	return rnode.relNode;
+	return rnode.node.relNode;
 }
diff --git a/src/backend/catalog/heap.c b/src/backend/catalog/heap.c
index 20d78a2..9403dc1 100644
--- a/src/backend/catalog/heap.c
+++ b/src/backend/catalog/heap.c
@@ -39,6 +39,7 @@
 #include "catalog/heap.h"
 #include "catalog/index.h"
 #include "catalog/indexing.h"
+#include "catalog/namespace.h"
 #include "catalog/pg_attrdef.h"
 #include "catalog/pg_constraint.h"
 #include "catalog/pg_inherits.h"
@@ -994,7 +995,9 @@ heap_create_with_catalog(const char *relname,
 			binary_upgrade_next_toast_relfilenode = InvalidOid;
 		}
 		else
-			relid = GetNewRelFileNode(reltablespace, pg_class_desc);
+			relid = GetNewRelFileNode(reltablespace, pg_class_desc,
+									  isTempOrToastNamespace(relnamespace) ?
+										  MyBackendId : InvalidBackendId);
 	}
 
 	/*
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 69946fe..3408a10 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -645,7 +645,12 @@ index_create(Oid heapRelationId,
 			binary_upgrade_next_index_relfilenode = InvalidOid;
 		}
 		else
-			indexRelationId = GetNewRelFileNode(tableSpaceId, pg_class);
+		{
+			indexRelationId =
+				GetNewRelFileNode(tableSpaceId, pg_class,
+								  heapRelation->rd_istemp ?
+									MyBackendId : InvalidBackendId);
+		}
 	}
 
 	/*
diff --git a/src/backend/catalog/storage.c b/src/backend/catalog/storage.c
index ad376a1..4515741 100644
--- a/src/backend/catalog/storage.c
+++ b/src/backend/catalog/storage.c
@@ -52,7 +52,7 @@
 typedef struct PendingRelDelete
 {
 	RelFileNode relnode;		/* relation that may need to be deleted */
-	bool		isTemp;			/* is it a temporary relation? */
+	BackendId	backend;		/* InvalidBackendId if not a temp rel */
 	bool		atCommit;		/* T=delete at commit; F=delete at abort */
 	int			nestLevel;		/* xact nesting level of request */
 	struct PendingRelDelete *next;		/* linked-list link */
@@ -102,8 +102,9 @@ RelationCreateStorage(RelFileNode rnode, bool istemp)
 	XLogRecData rdata;
 	xl_smgr_create xlrec;
 	SMgrRelation srel;
+	BackendId	backend = istemp ? MyBackendId : InvalidBackendId;
 
-	srel = smgropen(rnode);
+	srel = smgropen(rnode, backend);
 	smgrcreate(srel, MAIN_FORKNUM, false);
 
 	if (!istemp)
@@ -125,7 +126,7 @@ RelationCreateStorage(RelFileNode rnode, bool istemp)
 	pending = (PendingRelDelete *)
 		MemoryContextAlloc(TopMemoryContext, sizeof(PendingRelDelete));
 	pending->relnode = rnode;
-	pending->isTemp = istemp;
+	pending->backend = backend;
 	pending->atCommit = false;	/* delete if abort */
 	pending->nestLevel = GetCurrentTransactionNestLevel();
 	pending->next = pendingDeletes;
@@ -145,7 +146,7 @@ RelationDropStorage(Relation rel)
 	pending = (PendingRelDelete *)
 		MemoryContextAlloc(TopMemoryContext, sizeof(PendingRelDelete));
 	pending->relnode = rel->rd_node;
-	pending->isTemp = rel->rd_istemp;
+	pending->backend = rel->rd_backend;
 	pending->atCommit = true;	/* delete if commit */
 	pending->nestLevel = GetCurrentTransactionNestLevel();
 	pending->next = pendingDeletes;
@@ -283,7 +284,7 @@ RelationTruncate(Relation rel, BlockNumber nblocks)
 	}
 
 	/* Do the real work */
-	smgrtruncate(rel->rd_smgr, MAIN_FORKNUM, nblocks, rel->rd_istemp);
+	smgrtruncate(rel->rd_smgr, MAIN_FORKNUM, nblocks);
 }
 
 /*
@@ -322,14 +323,11 @@ smgrDoPendingDeletes(bool isCommit)
 				SMgrRelation srel;
 				int			i;
 
-				srel = smgropen(pending->relnode);
+				srel = smgropen(pending->relnode, pending->backend);
 				for (i = 0; i <= MAX_FORKNUM; i++)
 				{
 					if (smgrexists(srel, i))
-						smgrdounlink(srel,
-									 i,
-									 pending->isTemp,
-									 false);
+						smgrdounlink(srel, i, false);
 				}
 				smgrclose(srel);
 			}
@@ -341,20 +339,24 @@ smgrDoPendingDeletes(bool isCommit)
 }
 
 /*
- * smgrGetPendingDeletes() -- Get a list of relations to be deleted.
+ * smgrGetPendingDeletes() -- Get a list of non-temp relations to be deleted.
  *
  * The return value is the number of relations scheduled for termination.
  * *ptr is set to point to a freshly-palloc'd array of RelFileNodes.
  * If there are no relations to be deleted, *ptr is set to NULL.
  *
- * If haveNonTemp isn't NULL, the bool it points to gets set to true if
- * there is any non-temp table pending to be deleted; false if not.
+ * Only non-temporary relations are included in the returned list.  This is OK
+ * because the list is used only in contexts where temporary relations don't
+ * matter: we're either writing to the two-phase state file (and transactions
+ * that have touched temp tables can't be prepared) or we're writing to xlog
+ * (and all temporary files will be zapped if we restart anyway, so no need
+ * for redo to do it also).
  *
  * Note that the list does not include anything scheduled for termination
  * by upper-level transactions.
  */
 int
-smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr, bool *haveNonTemp)
+smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr)
 {
 	int			nestLevel = GetCurrentTransactionNestLevel();
 	int			nrels;
@@ -362,11 +364,10 @@ smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr, bool *haveNonTemp)
 	PendingRelDelete *pending;
 
 	nrels = 0;
-	if (haveNonTemp)
-		*haveNonTemp = false;
 	for (pending = pendingDeletes; pending != NULL; pending = pending->next)
 	{
-		if (pending->nestLevel >= nestLevel && pending->atCommit == forCommit)
+		if (pending->nestLevel >= nestLevel && pending->atCommit == forCommit
+			&& pending->backend == InvalidBackendId)
 			nrels++;
 	}
 	if (nrels == 0)
@@ -378,13 +379,12 @@ smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr, bool *haveNonTemp)
 	*ptr = rptr;
 	for (pending = pendingDeletes; pending != NULL; pending = pending->next)
 	{
-		if (pending->nestLevel >= nestLevel && pending->atCommit == forCommit)
+		if (pending->nestLevel >= nestLevel && pending->atCommit == forCommit
+			&& pending->backend == InvalidBackendId)
 		{
 			*rptr = pending->relnode;
 			rptr++;
 		}
-		if (haveNonTemp && !pending->isTemp)
-			*haveNonTemp = true;
 	}
 	return nrels;
 }
@@ -456,7 +456,7 @@ smgr_redo(XLogRecPtr lsn, XLogRecord *record)
 		xl_smgr_create *xlrec = (xl_smgr_create *) XLogRecGetData(record);
 		SMgrRelation reln;
 
-		reln = smgropen(xlrec->rnode);
+		reln = smgropen(xlrec->rnode, InvalidBackendId);
 		smgrcreate(reln, MAIN_FORKNUM, true);
 	}
 	else if (info == XLOG_SMGR_TRUNCATE)
@@ -465,7 +465,7 @@ smgr_redo(XLogRecPtr lsn, XLogRecord *record)
 		SMgrRelation reln;
 		Relation	rel;
 
-		reln = smgropen(xlrec->rnode);
+		reln = smgropen(xlrec->rnode, InvalidBackendId);
 
 		/*
 		 * Forcibly create relation if it doesn't exist (which suggests that
@@ -475,7 +475,7 @@ smgr_redo(XLogRecPtr lsn, XLogRecord *record)
 		 */
 		smgrcreate(reln, MAIN_FORKNUM, true);
 
-		smgrtruncate(reln, MAIN_FORKNUM, xlrec->blkno, false);
+		smgrtruncate(reln, MAIN_FORKNUM, xlrec->blkno);
 
 		/* Also tell xlogutils.c about it */
 		XLogTruncateRelation(xlrec->rnode, MAIN_FORKNUM, xlrec->blkno);
@@ -502,7 +502,7 @@ smgr_desc(StringInfo buf, uint8 xl_info, char *rec)
 	if (info == XLOG_SMGR_CREATE)
 	{
 		xl_smgr_create *xlrec = (xl_smgr_create *) rec;
-		char	   *path = relpath(xlrec->rnode, MAIN_FORKNUM);
+		char	   *path = relpathperm(xlrec->rnode, MAIN_FORKNUM);
 
 		appendStringInfo(buf, "file create: %s", path);
 		pfree(path);
@@ -510,7 +510,7 @@ smgr_desc(StringInfo buf, uint8 xl_info, char *rec)
 	else if (info == XLOG_SMGR_TRUNCATE)
 	{
 		xl_smgr_truncate *xlrec = (xl_smgr_truncate *) rec;
-		char	   *path = relpath(xlrec->rnode, MAIN_FORKNUM);
+		char	   *path = relpathperm(xlrec->rnode, MAIN_FORKNUM);
 
 		appendStringInfo(buf, "file truncate: %s to %u blocks", path,
 						 xlrec->blkno);
diff --git a/src/backend/catalog/toasting.c b/src/backend/catalog/toasting.c
index 52eef7c..fbdc423 100644
--- a/src/backend/catalog/toasting.c
+++ b/src/backend/catalog/toasting.c
@@ -195,7 +195,7 @@ create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid, Datum reloptio
 	 * Toast tables for regular relations go in pg_toast; those for temp
 	 * relations go into the per-backend temp-toast-table namespace.
 	 */
-	if (rel->rd_islocaltemp)
+	if (rel->rd_backend == MyBackendId)
 		namespaceid = GetTempToastNamespace();
 	else
 		namespaceid = PG_TOAST_NAMESPACE;
diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c
index 906d547..31e19bc 100644
--- a/src/backend/commands/copy.c
+++ b/src/backend/commands/copy.c
@@ -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 66b67dd..3bf067e 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -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 2ec1476..067e207 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -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
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c
index 95e9d37..cf79de3 100644
--- a/src/backend/postmaster/bgwriter.c
+++ b/src/backend/postmaster/bgwriter.c
@@ -113,7 +113,7 @@
  */
 typedef struct
 {
-	RelFileNode rnode;
+	BackendRelFileNode rnode;
 	ForkNumber	forknum;
 	BlockNumber segno;			/* see md.c for special values */
 	/* might add a real request-type field later; not needed yet */
@@ -1071,7 +1071,8 @@ RequestCheckpoint(int flags)
  * than we have to here.
  */
 bool
-ForwardFsyncRequest(RelFileNode rnode, ForkNumber forknum, BlockNumber segno)
+ForwardFsyncRequest(BackendRelFileNode rnode, ForkNumber forknum,
+					BlockNumber segno)
 {
 	BgWriterRequest *request;
 
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index caae936..4dd894b 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -95,7 +95,8 @@ static void WaitIO(volatile BufferDesc *buf);
 static bool StartBufferIO(volatile BufferDesc *buf, bool forInput);
 static void TerminateBufferIO(volatile BufferDesc *buf, bool clear_dirty,
 				  int set_flag_bits);
-static void buffer_write_error_callback(void *arg);
+static void shared_buffer_write_error_callback(void *arg);
+static void local_buffer_write_error_callback(void *arg);
 static volatile BufferDesc *BufferAlloc(SMgrRelation smgr, ForkNumber forkNum,
 			BlockNumber blockNum,
 			BufferAccessStrategy strategy,
@@ -141,7 +142,8 @@ PrefetchBuffer(Relation reln, ForkNumber forkNum, BlockNumber blockNum)
 		int			buf_id;
 
 		/* create a tag so we can lookup the buffer */
-		INIT_BUFFERTAG(newTag, reln->rd_smgr->smgr_rnode, forkNum, blockNum);
+		INIT_BUFFERTAG(newTag, reln->rd_smgr->smgr_rnode.node,
+					   forkNum, blockNum);
 
 		/* determine its hash code and partition lock ID */
 		newHash = BufTableHashCode(&newTag);
@@ -251,18 +253,21 @@ ReadBufferExtended(Relation reln, ForkNumber forkNum, BlockNumber blockNum,
  * ReadBufferWithoutRelcache -- like ReadBufferExtended, but doesn't require
  *		a relcache entry for the relation.
  *
- * NB: caller is assumed to know what it's doing if isTemp is true.
+ * NB: At present, this function may not be used on temporary relations, which
+ * is OK, because we only use it during XLOG replay.  If in the future we
+ * want to use it on temporary relations, we could pass the backend ID as an
+ * additional parameter.
  */
 Buffer
-ReadBufferWithoutRelcache(RelFileNode rnode, bool isTemp,
-						  ForkNumber forkNum, BlockNumber blockNum,
-						  ReadBufferMode mode, BufferAccessStrategy strategy)
+ReadBufferWithoutRelcache(RelFileNode rnode, ForkNumber forkNum,
+						  BlockNumber blockNum, ReadBufferMode mode,
+						  BufferAccessStrategy strategy)
 {
 	bool		hit;
 
-	SMgrRelation smgr = smgropen(rnode);
+	SMgrRelation smgr = smgropen(rnode, InvalidBackendId);
 
-	return ReadBuffer_common(smgr, isTemp, forkNum, blockNum, mode, strategy,
+	return ReadBuffer_common(smgr, false, forkNum, blockNum, mode, strategy,
 							 &hit);
 }
 
@@ -414,7 +419,7 @@ ReadBuffer_common(SMgrRelation smgr, bool isLocalBuf, ForkNumber forkNum,
 	{
 		/* new buffers are zero-filled */
 		MemSet((char *) bufBlock, 0, BLCKSZ);
-		smgrextend(smgr, forkNum, blockNum, (char *) bufBlock, isLocalBuf);
+		smgrextend(smgr, forkNum, blockNum, (char *) bufBlock, false);
 	}
 	else
 	{
@@ -465,10 +470,10 @@ ReadBuffer_common(SMgrRelation smgr, bool isLocalBuf, ForkNumber forkNum,
 		VacuumCostBalance += VacuumCostPageMiss;
 
 	TRACE_POSTGRESQL_BUFFER_READ_DONE(forkNum, blockNum,
-									  smgr->smgr_rnode.spcNode,
-									  smgr->smgr_rnode.dbNode,
-									  smgr->smgr_rnode.relNode,
-									  isLocalBuf,
+									  smgr->smgr_rnode.node.spcNode,
+									  smgr->smgr_rnode.node.dbNode,
+									  smgr->smgr_rnode.node.relNode,
+									  smgr->smgr_rnode.backend,
 									  isExtend,
 									  found);
 
@@ -512,7 +517,7 @@ BufferAlloc(SMgrRelation smgr, ForkNumber forkNum,
 	bool		valid;
 
 	/* create a tag so we can lookup the buffer */
-	INIT_BUFFERTAG(newTag, smgr->smgr_rnode, forkNum, blockNum);
+	INIT_BUFFERTAG(newTag, smgr->smgr_rnode.node, forkNum, blockNum);
 
 	/* determine its hash code and partition lock ID */
 	newHash = BufTableHashCode(&newTag);
@@ -1693,21 +1698,24 @@ PrintBufferLeakWarning(Buffer buffer)
 	volatile BufferDesc *buf;
 	int32		loccount;
 	char	   *path;
+	BackendId	backend;
 
 	Assert(BufferIsValid(buffer));
 	if (BufferIsLocal(buffer))
 	{
 		buf = &LocalBufferDescriptors[-buffer - 1];
 		loccount = LocalRefCount[-buffer - 1];
+		backend = MyBackendId;
 	}
 	else
 	{
 		buf = &BufferDescriptors[buffer - 1];
 		loccount = PrivateRefCount[buffer - 1];
+		backend = InvalidBackendId;
 	}
 
 	/* theoretically we should lock the bufhdr here */
-	path = relpath(buf->tag.rnode, buf->tag.forkNum);
+	path = relpathbackend(buf->tag.rnode, backend, buf->tag.forkNum);
 	elog(WARNING,
 		 "buffer refcount leak: [%03d] "
 		 "(rel=%s, blockNum=%u, flags=0x%x, refcount=%u %d)",
@@ -1831,14 +1839,14 @@ FlushBuffer(volatile BufferDesc *buf, SMgrRelation reln)
 		return;
 
 	/* Setup error traceback support for ereport() */
-	errcontext.callback = buffer_write_error_callback;
+	errcontext.callback = shared_buffer_write_error_callback;
 	errcontext.arg = (void *) buf;
 	errcontext.previous = error_context_stack;
 	error_context_stack = &errcontext;
 
 	/* Find smgr relation for buffer */
 	if (reln == NULL)
-		reln = smgropen(buf->tag.rnode);
+		reln = smgropen(buf->tag.rnode, InvalidBackendId);
 
 	TRACE_POSTGRESQL_BUFFER_FLUSH_START(buf->tag.forkNum,
 										buf->tag.blockNum,
@@ -1929,14 +1937,15 @@ RelationGetNumberOfBlocks(Relation relation)
  * --------------------------------------------------------------------
  */
 void
-DropRelFileNodeBuffers(RelFileNode rnode, ForkNumber forkNum, bool istemp,
+DropRelFileNodeBuffers(BackendRelFileNode rnode, ForkNumber forkNum,
 					   BlockNumber firstDelBlock)
 {
 	int			i;
 
-	if (istemp)
+	if (rnode.backend != InvalidBackendId)
 	{
-		DropRelFileNodeLocalBuffers(rnode, forkNum, firstDelBlock);
+		if (rnode.backend == MyBackendId)
+			DropRelFileNodeLocalBuffers(rnode.node, forkNum, firstDelBlock);
 		return;
 	}
 
@@ -1945,7 +1954,7 @@ DropRelFileNodeBuffers(RelFileNode rnode, ForkNumber forkNum, bool istemp,
 		volatile BufferDesc *bufHdr = &BufferDescriptors[i];
 
 		LockBufHdr(bufHdr);
-		if (RelFileNodeEquals(bufHdr->tag.rnode, rnode) &&
+		if (RelFileNodeEquals(bufHdr->tag.rnode, rnode.node) &&
 			bufHdr->tag.forkNum == forkNum &&
 			bufHdr->tag.blockNum >= firstDelBlock)
 			InvalidateBuffer(bufHdr);	/* releases spinlock */
@@ -2008,7 +2017,7 @@ PrintBufferDescs(void)
 			 "[%02d] (freeNext=%d, rel=%s, "
 			 "blockNum=%u, flags=0x%x, refcount=%u %d)",
 			 i, buf->freeNext,
-			 relpath(buf->tag.rnode, buf->tag.forkNum),
+			 relpathbackend(buf->tag.rnode, InvalidBackendId, buf->tag.forkNum),
 			 buf->tag.blockNum, buf->flags,
 			 buf->refcount, PrivateRefCount[i]);
 	}
@@ -2078,7 +2087,7 @@ FlushRelationBuffers(Relation rel)
 				ErrorContextCallback errcontext;
 
 				/* Setup error traceback support for ereport() */
-				errcontext.callback = buffer_write_error_callback;
+				errcontext.callback = local_buffer_write_error_callback;
 				errcontext.arg = (void *) bufHdr;
 				errcontext.previous = error_context_stack;
 				error_context_stack = &errcontext;
@@ -2087,7 +2096,7 @@ FlushRelationBuffers(Relation rel)
 						  bufHdr->tag.forkNum,
 						  bufHdr->tag.blockNum,
 						  (char *) LocalBufHdrGetBlock(bufHdr),
-						  true);
+						  false);
 
 				bufHdr->flags &= ~(BM_DIRTY | BM_JUST_DIRTIED);
 
@@ -2699,8 +2708,9 @@ AbortBufferIO(void)
 			if (sv_flags & BM_IO_ERROR)
 			{
 				/* Buffer is pinned, so we can read tag without spinlock */
-				char	   *path = relpath(buf->tag.rnode, buf->tag.forkNum);
+				char	   *path;
 
+				path = relpathperm(buf->tag.rnode, buf->tag.forkNum);
 				ereport(WARNING,
 						(errcode(ERRCODE_IO_ERROR),
 						 errmsg("could not write block %u of %s",
@@ -2714,17 +2724,36 @@ AbortBufferIO(void)
 }
 
 /*
- * Error context callback for errors occurring during buffer writes.
+ * Error context callback for errors occurring during shared buffer writes.
  */
 static void
-buffer_write_error_callback(void *arg)
+shared_buffer_write_error_callback(void *arg)
 {
 	volatile BufferDesc *bufHdr = (volatile BufferDesc *) arg;
 
 	/* Buffer is pinned, so we can read the tag without locking the spinlock */
 	if (bufHdr != NULL)
 	{
-		char	   *path = relpath(bufHdr->tag.rnode, bufHdr->tag.forkNum);
+		char	   *path = relpathperm(bufHdr->tag.rnode, bufHdr->tag.forkNum);
+
+		errcontext("writing block %u of relation %s",
+				   bufHdr->tag.blockNum, path);
+		pfree(path);
+	}
+}
+
+/*
+ * Error context callback for errors occurring during buffer writes.
+ */
+static void
+local_buffer_write_error_callback(void *arg)
+{
+	volatile BufferDesc *bufHdr = (volatile BufferDesc *) arg;
+
+	if (bufHdr != NULL)
+	{
+		char	   *path = relpathbackend(bufHdr->tag.rnode, MyBackendId,
+										 bufHdr->tag.forkNum);
 
 		errcontext("writing block %u of relation %s",
 				   bufHdr->tag.blockNum, path);
diff --git a/src/backend/storage/buffer/localbuf.c b/src/backend/storage/buffer/localbuf.c
index c5b6a2c..bbf0a01 100644
--- a/src/backend/storage/buffer/localbuf.c
+++ b/src/backend/storage/buffer/localbuf.c
@@ -68,7 +68,7 @@ LocalPrefetchBuffer(SMgrRelation smgr, ForkNumber forkNum,
 	BufferTag	newTag;			/* identity of requested block */
 	LocalBufferLookupEnt *hresult;
 
-	INIT_BUFFERTAG(newTag, smgr->smgr_rnode, forkNum, blockNum);
+	INIT_BUFFERTAG(newTag, smgr->smgr_rnode.node, forkNum, blockNum);
 
 	/* Initialize local buffers if first request in this session */
 	if (LocalBufHash == NULL)
@@ -110,7 +110,7 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
 	int			trycounter;
 	bool		found;
 
-	INIT_BUFFERTAG(newTag, smgr->smgr_rnode, forkNum, blockNum);
+	INIT_BUFFERTAG(newTag, smgr->smgr_rnode.node, forkNum, blockNum);
 
 	/* Initialize local buffers if first request in this session */
 	if (LocalBufHash == NULL)
@@ -127,7 +127,7 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
 		Assert(BUFFERTAGS_EQUAL(bufHdr->tag, newTag));
 #ifdef LBDEBUG
 		fprintf(stderr, "LB ALLOC (%u,%d,%d) %d\n",
-				smgr->smgr_rnode.relNode, forkNum, blockNum, -b - 1);
+				smgr->smgr_rnode.node.relNode, forkNum, blockNum, -b - 1);
 #endif
 		/* this part is equivalent to PinBuffer for a shared buffer */
 		if (LocalRefCount[b] == 0)
@@ -150,7 +150,8 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
 
 #ifdef LBDEBUG
 	fprintf(stderr, "LB ALLOC (%u,%d,%d) %d\n",
-		 smgr->smgr_rnode.relNode, forkNum, blockNum, -nextFreeLocalBuf - 1);
+		 smgr->smgr_rnode.node.relNode, forkNum, blockNum,
+		 -nextFreeLocalBuf - 1);
 #endif
 
 	/*
@@ -198,14 +199,14 @@ LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum, BlockNumber blockNum,
 		SMgrRelation oreln;
 
 		/* Find smgr relation for buffer */
-		oreln = smgropen(bufHdr->tag.rnode);
+		oreln = smgropen(bufHdr->tag.rnode, MyBackendId);
 
 		/* And write... */
 		smgrwrite(oreln,
 				  bufHdr->tag.forkNum,
 				  bufHdr->tag.blockNum,
 				  (char *) LocalBufHdrGetBlock(bufHdr),
-				  true);
+				  false);
 
 		/* Mark not-dirty now in case we error out below */
 		bufHdr->flags &= ~BM_DIRTY;
@@ -309,7 +310,8 @@ DropRelFileNodeLocalBuffers(RelFileNode rnode, ForkNumber forkNum,
 			if (LocalRefCount[i] != 0)
 				elog(ERROR, "block %u of %s is still referenced (local %u)",
 					 bufHdr->tag.blockNum,
-					 relpath(bufHdr->tag.rnode, bufHdr->tag.forkNum),
+					 relpathbackend(bufHdr->tag.rnode, MyBackendId,
+								   bufHdr->tag.forkNum),
 					 LocalRefCount[i]);
 			/* Remove entry from hashtable */
 			hresult = (LocalBufferLookupEnt *)
diff --git a/src/backend/storage/file/fd.c b/src/backend/storage/file/fd.c
index 1d2eeec..3fb5844 100644
--- a/src/backend/storage/file/fd.c
+++ b/src/backend/storage/file/fd.c
@@ -249,6 +249,9 @@ static File OpenTemporaryFileInTablespace(Oid tblspcOid, bool rejectError);
 static void AtProcExit_Files(int code, Datum arg);
 static void CleanupTempFiles(bool isProcExit);
 static void RemovePgTempFilesInDir(const char *tmpdirname);
+static void RemovePgTempRelationFiles(const char *tsdirname);
+static void RemovePgTempRelationFilesInDbspace(const char *dbspacedirname);
+static bool looks_like_temp_rel_name(const char *name);
 
 
 /*
@@ -1824,10 +1827,12 @@ CleanupTempFiles(bool isProcExit)
 
 
 /*
- * Remove temporary files left over from a prior postmaster session
+ * Remove temporary and temporary relation files left over from a prior
+ * postmaster session
  *
  * This should be called during postmaster startup.  It will forcibly
- * remove any leftover files created by OpenTemporaryFile.
+ * remove any leftover files created by OpenTemporaryFile and any leftover
+ * temporary relation files created by mdcreate.
  *
  * NOTE: we could, but don't, call this during a post-backend-crash restart
  * cycle.  The argument for not doing it is that someone might want to examine
@@ -1847,6 +1852,7 @@ RemovePgTempFiles(void)
 	 */
 	snprintf(temp_path, sizeof(temp_path), "base/%s", PG_TEMP_FILES_DIR);
 	RemovePgTempFilesInDir(temp_path);
+	RemovePgTempRelationFiles("base");
 
 	/*
 	 * Cycle through temp directories for all non-default tablespaces.
@@ -1862,6 +1868,10 @@ RemovePgTempFiles(void)
 		snprintf(temp_path, sizeof(temp_path), "pg_tblspc/%s/%s/%s",
 			spc_de->d_name, TABLESPACE_VERSION_DIRECTORY, PG_TEMP_FILES_DIR);
 		RemovePgTempFilesInDir(temp_path);
+
+		snprintf(temp_path, sizeof(temp_path), "pg_tblspc/%s/%s",
+			spc_de->d_name, TABLESPACE_VERSION_DIRECTORY);
+		RemovePgTempRelationFiles(temp_path);
 	}
 
 	FreeDir(spc_dir);
@@ -1915,3 +1925,123 @@ RemovePgTempFilesInDir(const char *tmpdirname)
 
 	FreeDir(temp_dir);
 }
+
+/* Process one tablespace directory, look for per-DB subdirectories */
+static void
+RemovePgTempRelationFiles(const char *tsdirname)
+{
+	DIR		   *ts_dir;
+	struct dirent *de;
+	char		dbspace_path[MAXPGPATH];
+
+	ts_dir = AllocateDir(tsdirname);
+	if (ts_dir == NULL)
+	{
+		/* anything except ENOENT is fishy */
+		if (errno != ENOENT)
+			elog(LOG,
+				 "could not open tablespace directory \"%s\": %m",
+				 tsdirname);
+		return;
+	}
+
+	while ((de = ReadDir(ts_dir, tsdirname)) != NULL)
+	{
+		int		i = 0;
+
+		/*
+		 * We're only interested in the per-database directories, which have
+		 * numeric names.  Note that this code will also (properly) ignore "."
+		 * and "..".
+		 */
+		while (isdigit((unsigned char) de->d_name[i]))
+			++i;
+		if (de->d_name[i] != '\0' || i == 0)
+			continue;
+
+		snprintf(dbspace_path, sizeof(dbspace_path), "%s/%s",
+				 tsdirname, de->d_name);
+		RemovePgTempRelationFilesInDbspace(dbspace_path);
+	}
+
+	FreeDir(ts_dir);
+}
+
+/* Process one per-dbspace directory for RemovePgTempRelationFiles */
+static void
+RemovePgTempRelationFilesInDbspace(const char *dbspacedirname)
+{
+	DIR		   *dbspace_dir;
+	struct dirent *de;
+	char		rm_path[MAXPGPATH];
+
+	dbspace_dir = AllocateDir(dbspacedirname);
+	if (dbspace_dir == NULL)
+	{
+		/* we just saw this directory, so it really ought to be there */
+		elog(LOG,
+			 "could not open dbspace directory \"%s\": %m",
+			 dbspacedirname);
+		return;
+	}
+
+	while ((de = ReadDir(dbspace_dir, dbspacedirname)) != NULL)
+	{
+		if (!looks_like_temp_rel_name(de->d_name))
+			continue;
+
+		snprintf(rm_path, sizeof(rm_path), "%s/%s",
+				 dbspacedirname, de->d_name);
+
+		unlink(rm_path);	/* note we ignore any error */
+	}
+
+	FreeDir(dbspace_dir);
+}
+
+/* t<digits>_<digits>, or t<digits>_<digits>_<forkname> */
+static bool
+looks_like_temp_rel_name(const char *name)
+{
+	int			pos;
+	int			savepos;
+
+	/* Must start with "t". */
+	if (name[0] != 't')
+		return false;
+
+	/* Followed by a non-empty string of digits and then an underscore. */
+	for (pos = 1; isdigit((unsigned char) name[pos]); ++pos)
+		;
+	if (pos == 1 || name[pos] != '_')
+		return false;
+
+	/* Followed by another nonempty string of digits. */
+	for (savepos = ++pos; isdigit((unsigned char) name[pos]); ++pos)
+		;
+	if (savepos == pos)
+		return false;
+
+	/* We might have _forkname or .segment or both. */
+	if (name[pos] == '_')
+	{
+		int		forkchar = forkname_chars(&name[pos+1]);
+		if (forkchar <= 0)
+			return false;
+		pos += forkchar + 1;
+	}
+	if (name[pos] == '.')
+	{
+		int		segchar;
+		for (segchar = 1; isdigit((unsigned char) name[pos+segchar]); ++segchar)
+			;
+		if (segchar <= 1)
+			return false;
+		pos += segchar;
+	}
+
+	/* Now we should be at the end. */
+	if (name[pos] != '\0')
+		return false;
+	return true;
+}
diff --git a/src/backend/storage/freespace/freespace.c b/src/backend/storage/freespace/freespace.c
index 579572f..b43a2ce 100644
--- a/src/backend/storage/freespace/freespace.c
+++ b/src/backend/storage/freespace/freespace.c
@@ -303,7 +303,7 @@ FreeSpaceMapTruncateRel(Relation rel, BlockNumber nblocks)
 	}
 
 	/* Truncate the unused FSM pages, and send smgr inval message */
-	smgrtruncate(rel->rd_smgr, FSM_FORKNUM, new_nfsmblocks, rel->rd_istemp);
+	smgrtruncate(rel->rd_smgr, FSM_FORKNUM, new_nfsmblocks);
 
 	/*
 	 * We might as well update the local smgr_fsm_nblocks setting.
diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.c
index 4163ca0..79805b4 100644
--- a/src/backend/storage/smgr/md.c
+++ b/src/backend/storage/smgr/md.c
@@ -119,7 +119,7 @@ static MemoryContext MdCxt;		/* context for all md.c allocations */
  */
 typedef struct
 {
-	RelFileNode rnode;			/* the targeted relation */
+	BackendRelFileNode rnode;	/* the targeted relation */
 	ForkNumber	forknum;
 	BlockNumber segno;			/* which segment */
 } PendingOperationTag;
@@ -135,7 +135,7 @@ typedef struct
 
 typedef struct
 {
-	RelFileNode rnode;			/* the dead relation to delete */
+	BackendRelFileNode rnode;	/* the dead relation to delete */
 	CycleCtr	cycle_ctr;		/* mdckpt_cycle_ctr when request was made */
 } PendingUnlinkEntry;
 
@@ -158,14 +158,14 @@ static MdfdVec *mdopen(SMgrRelation reln, ForkNumber forknum,
 	   ExtensionBehavior behavior);
 static void register_dirty_segment(SMgrRelation reln, ForkNumber forknum,
 					   MdfdVec *seg);
-static void register_unlink(RelFileNode rnode);
+static void register_unlink(BackendRelFileNode rnode);
 static MdfdVec *_fdvec_alloc(void);
 static char *_mdfd_segpath(SMgrRelation reln, ForkNumber forknum,
 			  BlockNumber segno);
 static MdfdVec *_mdfd_openseg(SMgrRelation reln, ForkNumber forkno,
 			  BlockNumber segno, int oflags);
 static MdfdVec *_mdfd_getseg(SMgrRelation reln, ForkNumber forkno,
-			 BlockNumber blkno, bool isTemp, ExtensionBehavior behavior);
+			 BlockNumber blkno, bool skipFsync, ExtensionBehavior behavior);
 static BlockNumber _mdnblocks(SMgrRelation reln, ForkNumber forknum,
 		   MdfdVec *seg);
 
@@ -321,7 +321,7 @@ mdcreate(SMgrRelation reln, ForkNumber forkNum, bool isRedo)
  * we are usually not in a transaction anymore when this is called.
  */
 void
-mdunlink(RelFileNode rnode, ForkNumber forkNum, bool isRedo)
+mdunlink(BackendRelFileNode rnode, ForkNumber forkNum, bool isRedo)
 {
 	char	   *path;
 	int			ret;
@@ -417,7 +417,7 @@ mdunlink(RelFileNode rnode, ForkNumber forkNum, bool isRedo)
  */
 void
 mdextend(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
-		 char *buffer, bool isTemp)
+		 char *buffer, bool skipFsync)
 {
 	off_t		seekpos;
 	int			nbytes;
@@ -440,7 +440,7 @@ mdextend(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 						relpath(reln->smgr_rnode, forknum),
 						InvalidBlockNumber)));
 
-	v = _mdfd_getseg(reln, forknum, blocknum, isTemp, EXTENSION_CREATE);
+	v = _mdfd_getseg(reln, forknum, blocknum, skipFsync, EXTENSION_CREATE);
 
 	seekpos = (off_t) BLCKSZ *(blocknum % ((BlockNumber) RELSEG_SIZE));
 
@@ -478,7 +478,7 @@ mdextend(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 				 errhint("Check free disk space.")));
 	}
 
-	if (!isTemp)
+	if (!skipFsync && !SmgrIsTemp(reln))
 		register_dirty_segment(reln, forknum, v);
 
 	Assert(_mdnblocks(reln, forknum, v) <= ((BlockNumber) RELSEG_SIZE));
@@ -605,9 +605,10 @@ mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 	MdfdVec    *v;
 
 	TRACE_POSTGRESQL_SMGR_MD_READ_START(forknum, blocknum,
-										reln->smgr_rnode.spcNode,
-										reln->smgr_rnode.dbNode,
-										reln->smgr_rnode.relNode);
+										reln->smgr_rnode.node.spcNode,
+										reln->smgr_rnode.node.dbNode,
+										reln->smgr_rnode.node.relNode,
+										reln->smgr_rnode.backend);
 
 	v = _mdfd_getseg(reln, forknum, blocknum, false, EXTENSION_FAIL);
 
@@ -624,9 +625,10 @@ mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 	nbytes = FileRead(v->mdfd_vfd, buffer, BLCKSZ);
 
 	TRACE_POSTGRESQL_SMGR_MD_READ_DONE(forknum, blocknum,
-									   reln->smgr_rnode.spcNode,
-									   reln->smgr_rnode.dbNode,
-									   reln->smgr_rnode.relNode,
+									   reln->smgr_rnode.node.spcNode,
+									   reln->smgr_rnode.node.dbNode,
+									   reln->smgr_rnode.node.relNode,
+									   reln->smgr_rnode.backend,
 									   nbytes,
 									   BLCKSZ);
 
@@ -666,7 +668,7 @@ mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
  */
 void
 mdwrite(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
-		char *buffer, bool isTemp)
+		char *buffer, bool skipFsync)
 {
 	off_t		seekpos;
 	int			nbytes;
@@ -678,11 +680,12 @@ mdwrite(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 #endif
 
 	TRACE_POSTGRESQL_SMGR_MD_WRITE_START(forknum, blocknum,
-										 reln->smgr_rnode.spcNode,
-										 reln->smgr_rnode.dbNode,
-										 reln->smgr_rnode.relNode);
+										 reln->smgr_rnode.node.spcNode,
+										 reln->smgr_rnode.node.dbNode,
+										 reln->smgr_rnode.node.relNode,
+										 reln->smgr_rnode.backend);
 
-	v = _mdfd_getseg(reln, forknum, blocknum, isTemp, EXTENSION_FAIL);
+	v = _mdfd_getseg(reln, forknum, blocknum, skipFsync, EXTENSION_FAIL);
 
 	seekpos = (off_t) BLCKSZ *(blocknum % ((BlockNumber) RELSEG_SIZE));
 
@@ -697,9 +700,10 @@ mdwrite(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 	nbytes = FileWrite(v->mdfd_vfd, buffer, BLCKSZ);
 
 	TRACE_POSTGRESQL_SMGR_MD_WRITE_DONE(forknum, blocknum,
-										reln->smgr_rnode.spcNode,
-										reln->smgr_rnode.dbNode,
-										reln->smgr_rnode.relNode,
+										reln->smgr_rnode.node.spcNode,
+										reln->smgr_rnode.node.dbNode,
+										reln->smgr_rnode.node.relNode,
+										reln->smgr_rnode.backend,
 										nbytes,
 										BLCKSZ);
 
@@ -720,7 +724,7 @@ mdwrite(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 				 errhint("Check free disk space.")));
 	}
 
-	if (!isTemp)
+	if (!skipFsync && !SmgrIsTemp(reln))
 		register_dirty_segment(reln, forknum, v);
 }
 
@@ -794,8 +798,7 @@ mdnblocks(SMgrRelation reln, ForkNumber forknum)
  *	mdtruncate() -- Truncate relation to specified number of blocks.
  */
 void
-mdtruncate(SMgrRelation reln, ForkNumber forknum, BlockNumber nblocks,
-		   bool isTemp)
+mdtruncate(SMgrRelation reln, ForkNumber forknum, BlockNumber nblocks)
 {
 	MdfdVec    *v;
 	BlockNumber curnblk;
@@ -839,7 +842,7 @@ mdtruncate(SMgrRelation reln, ForkNumber forknum, BlockNumber nblocks,
 						 errmsg("could not truncate file \"%s\": %m",
 								FilePathName(v->mdfd_vfd))));
 
-			if (!isTemp)
+			if (!SmgrIsTemp(reln))
 				register_dirty_segment(reln, forknum, v);
 			v = v->mdfd_chain;
 			Assert(ov != reln->md_fd[forknum]); /* we never drop the 1st
@@ -864,7 +867,7 @@ mdtruncate(SMgrRelation reln, ForkNumber forknum, BlockNumber nblocks,
 					errmsg("could not truncate file \"%s\" to %u blocks: %m",
 						   FilePathName(v->mdfd_vfd),
 						   nblocks)));
-			if (!isTemp)
+			if (!SmgrIsTemp(reln))
 				register_dirty_segment(reln, forknum, v);
 			v = v->mdfd_chain;
 			ov->mdfd_chain = NULL;
@@ -1052,7 +1055,8 @@ mdsync(void)
 				 * the relation will have been dirtied through this same smgr
 				 * relation, and so we can save a file open/close cycle.
 				 */
-				reln = smgropen(entry->tag.rnode);
+				reln = smgropen(entry->tag.rnode.node,
+								entry->tag.rnode.backend);
 
 				/*
 				 * It is possible that the relation has been dropped or
@@ -1235,7 +1239,7 @@ register_dirty_segment(SMgrRelation reln, ForkNumber forknum, MdfdVec *seg)
  * a remote pending-ops table.
  */
 static void
-register_unlink(RelFileNode rnode)
+register_unlink(BackendRelFileNode rnode)
 {
 	if (pendingOpsTable)
 	{
@@ -1278,7 +1282,8 @@ register_unlink(RelFileNode rnode)
  * structure for them.)
  */
 void
-RememberFsyncRequest(RelFileNode rnode, ForkNumber forknum, BlockNumber segno)
+RememberFsyncRequest(BackendRelFileNode rnode, ForkNumber forknum,
+					 BlockNumber segno)
 {
 	Assert(pendingOpsTable);
 
@@ -1291,7 +1296,7 @@ RememberFsyncRequest(RelFileNode rnode, ForkNumber forknum, BlockNumber segno)
 		hash_seq_init(&hstat, pendingOpsTable);
 		while ((entry = (PendingOperationEntry *) hash_seq_search(&hstat)) != NULL)
 		{
-			if (RelFileNodeEquals(entry->tag.rnode, rnode) &&
+			if (BackendRelFileNodeEquals(entry->tag.rnode, rnode) &&
 				entry->tag.forknum == forknum)
 			{
 				/* Okay, cancel this entry */
@@ -1312,7 +1317,7 @@ RememberFsyncRequest(RelFileNode rnode, ForkNumber forknum, BlockNumber segno)
 		hash_seq_init(&hstat, pendingOpsTable);
 		while ((entry = (PendingOperationEntry *) hash_seq_search(&hstat)) != NULL)
 		{
-			if (entry->tag.rnode.dbNode == rnode.dbNode)
+			if (entry->tag.rnode.node.dbNode == rnode.node.dbNode)
 			{
 				/* Okay, cancel this entry */
 				entry->canceled = true;
@@ -1326,7 +1331,7 @@ RememberFsyncRequest(RelFileNode rnode, ForkNumber forknum, BlockNumber segno)
 			PendingUnlinkEntry *entry = (PendingUnlinkEntry *) lfirst(cell);
 
 			next = lnext(cell);
-			if (entry->rnode.dbNode == rnode.dbNode)
+			if (entry->rnode.node.dbNode == rnode.node.dbNode)
 			{
 				pendingUnlinks = list_delete_cell(pendingUnlinks, cell, prev);
 				pfree(entry);
@@ -1393,7 +1398,7 @@ RememberFsyncRequest(RelFileNode rnode, ForkNumber forknum, BlockNumber segno)
  * ForgetRelationFsyncRequests -- forget any fsyncs for a rel
  */
 void
-ForgetRelationFsyncRequests(RelFileNode rnode, ForkNumber forknum)
+ForgetRelationFsyncRequests(BackendRelFileNode rnode, ForkNumber forknum)
 {
 	if (pendingOpsTable)
 	{
@@ -1428,11 +1433,12 @@ ForgetRelationFsyncRequests(RelFileNode rnode, ForkNumber forknum)
 void
 ForgetDatabaseFsyncRequests(Oid dbid)
 {
-	RelFileNode rnode;
+	BackendRelFileNode rnode;
 
-	rnode.dbNode = dbid;
-	rnode.spcNode = 0;
-	rnode.relNode = 0;
+	rnode.node.dbNode = dbid;
+	rnode.node.spcNode = 0;
+	rnode.node.relNode = 0;
+	rnode.backend = InvalidBackendId;
 
 	if (pendingOpsTable)
 	{
@@ -1523,12 +1529,12 @@ _mdfd_openseg(SMgrRelation reln, ForkNumber forknum, BlockNumber segno,
  *		specified block.
  *
  * If the segment doesn't exist, we ereport, return NULL, or create the
- * segment, according to "behavior".  Note: isTemp need only be correct
- * in the EXTENSION_CREATE case.
+ * segment, according to "behavior".  Note: skipFsync is only used in the
+ * EXTENSION_CREATE case.
  */
 static MdfdVec *
 _mdfd_getseg(SMgrRelation reln, ForkNumber forknum, BlockNumber blkno,
-			 bool isTemp, ExtensionBehavior behavior)
+			 bool skipFsync, ExtensionBehavior behavior)
 {
 	MdfdVec    *v = mdopen(reln, forknum, behavior);
 	BlockNumber targetseg;
@@ -1566,7 +1572,7 @@ _mdfd_getseg(SMgrRelation reln, ForkNumber forknum, BlockNumber blkno,
 
 					mdextend(reln, forknum,
 							 nextsegno * ((BlockNumber) RELSEG_SIZE) - 1,
-							 zerobuf, isTemp);
+							 zerobuf, skipFsync);
 					pfree(zerobuf);
 				}
 				v->mdfd_chain = _mdfd_openseg(reln, forknum, +nextsegno, O_CREAT);
diff --git a/src/backend/storage/smgr/smgr.c b/src/backend/storage/smgr/smgr.c
index 3b12cb3..ecf238d 100644
--- a/src/backend/storage/smgr/smgr.c
+++ b/src/backend/storage/smgr/smgr.c
@@ -45,19 +45,19 @@ typedef struct f_smgr
 	void		(*smgr_create) (SMgrRelation reln, ForkNumber forknum,
 											bool isRedo);
 	bool		(*smgr_exists) (SMgrRelation reln, ForkNumber forknum);
-	void		(*smgr_unlink) (RelFileNode rnode, ForkNumber forknum,
+	void		(*smgr_unlink) (BackendRelFileNode rnode, ForkNumber forknum,
 											bool isRedo);
 	void		(*smgr_extend) (SMgrRelation reln, ForkNumber forknum,
-							BlockNumber blocknum, char *buffer, bool isTemp);
+							BlockNumber blocknum, char *buffer, bool skipFsync);
 	void		(*smgr_prefetch) (SMgrRelation reln, ForkNumber forknum,
 											  BlockNumber blocknum);
 	void		(*smgr_read) (SMgrRelation reln, ForkNumber forknum,
 										  BlockNumber blocknum, char *buffer);
 	void		(*smgr_write) (SMgrRelation reln, ForkNumber forknum,
-							BlockNumber blocknum, char *buffer, bool isTemp);
+							BlockNumber blocknum, char *buffer, bool skipFsync);
 	BlockNumber (*smgr_nblocks) (SMgrRelation reln, ForkNumber forknum);
 	void		(*smgr_truncate) (SMgrRelation reln, ForkNumber forknum,
-										   BlockNumber nblocks, bool isTemp);
+										   BlockNumber nblocks);
 	void		(*smgr_immedsync) (SMgrRelation reln, ForkNumber forknum);
 	void		(*smgr_pre_ckpt) (void);		/* may be NULL */
 	void		(*smgr_sync) (void);	/* may be NULL */
@@ -83,8 +83,6 @@ static HTAB *SMgrRelationHash = NULL;
 
 /* local function prototypes */
 static void smgrshutdown(int code, Datum arg);
-static void smgr_internal_unlink(RelFileNode rnode, ForkNumber forknum,
-					 int which, bool isTemp, bool isRedo);
 
 
 /*
@@ -131,8 +129,9 @@ smgrshutdown(int code, Datum arg)
  *		This does not attempt to actually open the object.
  */
 SMgrRelation
-smgropen(RelFileNode rnode)
+smgropen(RelFileNode rnode, BackendId backend)
 {
+	BackendRelFileNode brnode;
 	SMgrRelation reln;
 	bool		found;
 
@@ -142,7 +141,7 @@ smgropen(RelFileNode rnode)
 		HASHCTL		ctl;
 
 		MemSet(&ctl, 0, sizeof(ctl));
-		ctl.keysize = sizeof(RelFileNode);
+		ctl.keysize = sizeof(BackendRelFileNode);
 		ctl.entrysize = sizeof(SMgrRelationData);
 		ctl.hash = tag_hash;
 		SMgrRelationHash = hash_create("smgr relation table", 400,
@@ -150,8 +149,10 @@ smgropen(RelFileNode rnode)
 	}
 
 	/* Look up or create an entry */
+	brnode.node = rnode;
+	brnode.backend = backend;
 	reln = (SMgrRelation) hash_search(SMgrRelationHash,
-									  (void *) &rnode,
+									  (void *) &brnode,
 									  HASH_ENTER, &found);
 
 	/* Initialize it if not present before */
@@ -261,7 +262,7 @@ smgrcloseall(void)
  * such entry exists already.
  */
 void
-smgrclosenode(RelFileNode rnode)
+smgrclosenode(BackendRelFileNode rnode)
 {
 	SMgrRelation reln;
 
@@ -305,8 +306,8 @@ smgrcreate(SMgrRelation reln, ForkNumber forknum, bool isRedo)
 	 * should be here and not in commands/tablespace.c?  But that would imply
 	 * importing a lot of stuff that smgr.c oughtn't know, either.
 	 */
-	TablespaceCreateDbspace(reln->smgr_rnode.spcNode,
-							reln->smgr_rnode.dbNode,
+	TablespaceCreateDbspace(reln->smgr_rnode.node.spcNode,
+							reln->smgr_rnode.node.dbNode,
 							isRedo);
 
 	(*(smgrsw[reln->smgr_which].smgr_create)) (reln, forknum, isRedo);
@@ -323,29 +324,19 @@ smgrcreate(SMgrRelation reln, ForkNumber forknum, bool isRedo)
  *		already.
  */
 void
-smgrdounlink(SMgrRelation reln, ForkNumber forknum, bool isTemp, bool isRedo)
+smgrdounlink(SMgrRelation reln, ForkNumber forknum, bool isRedo)
 {
-	RelFileNode rnode = reln->smgr_rnode;
+	BackendRelFileNode rnode = reln->smgr_rnode;
 	int			which = reln->smgr_which;
 
 	/* Close the fork */
 	(*(smgrsw[which].smgr_close)) (reln, forknum);
 
-	smgr_internal_unlink(rnode, forknum, which, isTemp, isRedo);
-}
-
-/*
- * Shared subroutine that actually does the unlink ...
- */
-static void
-smgr_internal_unlink(RelFileNode rnode, ForkNumber forknum,
-					 int which, bool isTemp, bool isRedo)
-{
 	/*
 	 * Get rid of any remaining buffers for the relation.  bufmgr will just
 	 * drop them without bothering to write the contents.
 	 */
-	DropRelFileNodeBuffers(rnode, forknum, isTemp, 0);
+	DropRelFileNodeBuffers(rnode, forknum, 0);
 
 	/*
 	 * It'd be nice to tell the stats collector to forget it immediately, too.
@@ -385,10 +376,10 @@ smgr_internal_unlink(RelFileNode rnode, ForkNumber forknum,
  */
 void
 smgrextend(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
-		   char *buffer, bool isTemp)
+		   char *buffer, bool skipFsync)
 {
 	(*(smgrsw[reln->smgr_which].smgr_extend)) (reln, forknum, blocknum,
-											   buffer, isTemp);
+											   buffer, skipFsync);
 }
 
 /*
@@ -426,16 +417,16 @@ smgrread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
  *		on disk at return, only dumped out to the kernel.  However,
  *		provisions will be made to fsync the write before the next checkpoint.
  *
- *		isTemp indicates that the relation is a temp table (ie, is managed
- *		by the local-buffer manager).  In this case no provisions need be
- *		made to fsync the write before checkpointing.
+ *		skipFsync indicates that the caller will make other provisions to
+ *		fsync the relation, so we needn't bother.  Temporary relations also
+ *		do not require fsync.
  */
 void
 smgrwrite(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
-		  char *buffer, bool isTemp)
+		  char *buffer, bool skipFsync)
 {
 	(*(smgrsw[reln->smgr_which].smgr_write)) (reln, forknum, blocknum,
-											  buffer, isTemp);
+											  buffer, skipFsync);
 }
 
 /*
@@ -455,14 +446,13 @@ smgrnblocks(SMgrRelation reln, ForkNumber forknum)
  * The truncation is done immediately, so this can't be rolled back.
  */
 void
-smgrtruncate(SMgrRelation reln, ForkNumber forknum, BlockNumber nblocks,
-			 bool isTemp)
+smgrtruncate(SMgrRelation reln, ForkNumber forknum, BlockNumber nblocks)
 {
 	/*
 	 * Get rid of any buffers for the about-to-be-deleted blocks. bufmgr will
 	 * just drop them without bothering to write the contents.
 	 */
-	DropRelFileNodeBuffers(reln->smgr_rnode, forknum, isTemp, nblocks);
+	DropRelFileNodeBuffers(reln->smgr_rnode, forknum, nblocks);
 
 	/*
 	 * Send a shared-inval message to force other backends to close any smgr
@@ -479,8 +469,7 @@ smgrtruncate(SMgrRelation reln, ForkNumber forknum, BlockNumber nblocks,
 	/*
 	 * Do the truncation.
 	 */
-	(*(smgrsw[reln->smgr_which].smgr_truncate)) (reln, forknum, nblocks,
-												 isTemp);
+	(*(smgrsw[reln->smgr_which].smgr_truncate)) (reln, forknum, nblocks);
 }
 
 /*
@@ -499,7 +488,7 @@ smgrtruncate(SMgrRelation reln, ForkNumber forknum, BlockNumber nblocks,
  *		to use the WAL log for PITR or replication purposes: in that case
  *		we have to make WAL entries as well.)
  *
- *		The preceding writes should specify isTemp = true to avoid
+ *		The preceding writes should specify skipFsync = true to avoid
  *		duplicative fsyncs.
  *
  *		Note that you need to do FlushRelationBuffers() first if there is
diff --git a/src/backend/utils/adt/dbsize.c b/src/backend/utils/adt/dbsize.c
index 8ec6b71..4a5441f 100644
--- a/src/backend/utils/adt/dbsize.c
+++ b/src/backend/utils/adt/dbsize.c
@@ -244,14 +244,14 @@ pg_tablespace_size_name(PG_FUNCTION_ARGS)
  * calculate size of (one fork of) a relation
  */
 static int64
-calculate_relation_size(RelFileNode *rfn, ForkNumber forknum)
+calculate_relation_size(RelFileNode *rfn, BackendId backend, ForkNumber forknum)
 {
 	int64		totalsize = 0;
 	char	   *relationpath;
 	char		pathname[MAXPGPATH];
 	unsigned int segcount = 0;
 
-	relationpath = relpath(*rfn, forknum);
+	relationpath = relpathbackend(*rfn, backend, forknum);
 
 	for (segcount = 0;; segcount++)
 	{
@@ -291,7 +291,7 @@ pg_relation_size(PG_FUNCTION_ARGS)
 
 	rel = relation_open(relOid, AccessShareLock);
 
-	size = calculate_relation_size(&(rel->rd_node),
+	size = calculate_relation_size(&(rel->rd_node), rel->rd_backend,
 							  forkname_to_number(text_to_cstring(forkName)));
 
 	relation_close(rel, AccessShareLock);
@@ -315,12 +315,14 @@ calculate_toast_table_size(Oid toastrelid)
 
 	/* toast heap size, including FSM and VM size */
 	for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
-		size += calculate_relation_size(&(toastRel->rd_node), forkNum);
+		size += calculate_relation_size(&(toastRel->rd_node),
+										toastRel->rd_backend, forkNum);
 
 	/* toast index size, including FSM and VM size */
 	toastIdxRel = relation_open(toastRel->rd_rel->reltoastidxid, AccessShareLock);
 	for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
-		size += calculate_relation_size(&(toastIdxRel->rd_node), forkNum);
+		size += calculate_relation_size(&(toastIdxRel->rd_node),
+										toastIdxRel->rd_backend, forkNum);
 
 	relation_close(toastIdxRel, AccessShareLock);
 	relation_close(toastRel, AccessShareLock);
@@ -349,7 +351,8 @@ calculate_table_size(Oid relOid)
 	 * heap size, including FSM and VM
 	 */
 	for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
-		size += calculate_relation_size(&(rel->rd_node), forkNum);
+		size += calculate_relation_size(&(rel->rd_node), rel->rd_backend,
+										forkNum);
 
 	/*
 	 * Size of toast relation
@@ -392,7 +395,9 @@ calculate_indexes_size(Oid relOid)
 			idxRel = relation_open(idxOid, AccessShareLock);
 
 			for (forkNum = 0; forkNum <= MAX_FORKNUM; forkNum++)
-				size += calculate_relation_size(&(idxRel->rd_node), forkNum);
+				size += calculate_relation_size(&(idxRel->rd_node),
+												idxRel->rd_backend,
+												forkNum);
 
 			relation_close(idxRel, AccessShareLock);
 		}
@@ -563,6 +568,7 @@ pg_relation_filepath(PG_FUNCTION_ARGS)
 	HeapTuple	tuple;
 	Form_pg_class relform;
 	RelFileNode rnode;
+	BackendId	backend;
 	char	   *path;
 
 	tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relid));
@@ -600,12 +606,27 @@ pg_relation_filepath(PG_FUNCTION_ARGS)
 			break;
 	}
 
-	ReleaseSysCache(tuple);
-
 	if (!OidIsValid(rnode.relNode))
+	{
+		ReleaseSysCache(tuple);
 		PG_RETURN_NULL();
+	}
+
+	/* If temporary, determine owning backend. */
+	if (!relform->relistemp)
+		backend = InvalidBackendId;
+	else if (isTempOrToastNamespace(relform->relnamespace))
+		backend = MyBackendId;
+	else
+	{
+		/* Do it the hard way. */
+		backend = GetTempNamespaceBackendId(relform->relnamespace);
+		Assert(backend != InvalidOid);
+	}
+
+	ReleaseSysCache(tuple);
 
-	path = relpath(rnode, MAIN_FORKNUM);
+	path = relpathbackend(rnode, backend, MAIN_FORKNUM);
 
 	PG_RETURN_TEXT_P(cstring_to_text(path));
 }
diff --git a/src/backend/utils/cache/inval.c b/src/backend/utils/cache/inval.c
index 3b15d85..238127b 100644
--- a/src/backend/utils/cache/inval.c
+++ b/src/backend/utils/cache/inval.c
@@ -319,7 +319,8 @@ AddCatcacheInvalidationMessage(InvalidationListHeader *hdr,
 {
 	SharedInvalidationMessage msg;
 
-	msg.cc.id = (int16) id;
+	Assert(id < CHAR_MAX);
+	msg.cc.id = (int8) id;
 	msg.cc.tuplePtr = *tuplePtr;
 	msg.cc.dbId = dbId;
 	msg.cc.hashValue = hashValue;
@@ -513,7 +514,10 @@ LocalExecuteInvalidationMessage(SharedInvalidationMessage *msg)
 		 * We could have smgr entries for relations of other databases, so no
 		 * short-circuit test is possible here.
 		 */
-		smgrclosenode(msg->sm.rnode);
+		BackendRelFileNode	rnode;
+		rnode.node = msg->sm.rnode;
+		rnode.backend = (msg->sm.backend_hi << 16) | (int) msg->sm.backend_lo;
+		smgrclosenode(rnode);
 	}
 	else if (msg->id == SHAREDINVALRELMAP_ID)
 	{
@@ -1163,14 +1167,20 @@ CacheInvalidateRelcacheByRelid(Oid relid)
  * in commit/abort WAL entries.  Instead, calls to CacheInvalidateSmgr()
  * should happen in low-level smgr.c routines, which are executed while
  * replaying WAL as well as when creating it.
+ *
+ * Note: In order to avoid bloating SharedInvalidationMessage, we store only
+ * three bytes of the backend ID using what would otherwise be padding space.
+ * Thus, the maximum possible backend ID is 2^23-1.
  */
 void
-CacheInvalidateSmgr(RelFileNode rnode)
+CacheInvalidateSmgr(BackendRelFileNode rnode)
 {
 	SharedInvalidationMessage msg;
 
 	msg.sm.id = SHAREDINVALSMGR_ID;
-	msg.sm.rnode = rnode;
+	msg.sm.backend_hi = rnode.backend >> 16;
+	msg.sm.backend_lo = rnode.backend & 0xffff;
+	msg.sm.rnode = rnode.node;
 	SendSharedInvalidMessages(&msg, 1);
 }
 
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index dda69e8..bc355ca 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -858,10 +858,20 @@ RelationBuildDesc(Oid targetRelId, bool insertIt)
 	relation->rd_createSubid = InvalidSubTransactionId;
 	relation->rd_newRelfilenodeSubid = InvalidSubTransactionId;
 	relation->rd_istemp = relation->rd_rel->relistemp;
-	if (relation->rd_istemp)
-		relation->rd_islocaltemp = isTempOrToastNamespace(relation->rd_rel->relnamespace);
+	if (!relation->rd_istemp)
+		relation->rd_backend = InvalidBackendId;
+	else if (isTempOrToastNamespace(relation->rd_rel->relnamespace))
+		relation->rd_backend = MyBackendId;
 	else
-		relation->rd_islocaltemp = false;
+	{
+		/*
+		 * If it's a temporary table, but not one of ours, we have to use
+		 * the slow, grotty method to figure out the owning backend.
+		 */
+		relation->rd_backend =
+			GetTempNamespaceBackendId(relation->rd_rel->relnamespace);
+		Assert(relation->rd_backend != InvalidOid);
+	}
 
 	/*
 	 * initialize the tuple descriptor (relation->rd_att).
@@ -1424,7 +1434,7 @@ formrdesc(const char *relationName, Oid relationReltype,
 	relation->rd_createSubid = InvalidSubTransactionId;
 	relation->rd_newRelfilenodeSubid = InvalidSubTransactionId;
 	relation->rd_istemp = false;
-	relation->rd_islocaltemp = false;
+	relation->rd_backend = InvalidBackendId;
 
 	/*
 	 * initialize relation tuple form
@@ -2515,7 +2525,7 @@ RelationBuildLocalRelation(const char *relname,
 
 	/* it is temporary if and only if it is in my temp-table namespace */
 	rel->rd_istemp = isTempOrToastNamespace(relnamespace);
-	rel->rd_islocaltemp = rel->rd_istemp;
+	rel->rd_backend = rel->rd_istemp ? MyBackendId : InvalidBackendId;
 
 	/*
 	 * create a new tuple descriptor from the one passed in.  We do this
@@ -2629,7 +2639,7 @@ void
 RelationSetNewRelfilenode(Relation relation, TransactionId freezeXid)
 {
 	Oid			newrelfilenode;
-	RelFileNode newrnode;
+	BackendRelFileNode newrnode;
 	Relation	pg_class;
 	HeapTuple	tuple;
 	Form_pg_class classform;
@@ -2640,7 +2650,8 @@ RelationSetNewRelfilenode(Relation relation, TransactionId freezeXid)
 		   TransactionIdIsNormal(freezeXid));
 
 	/* Allocate a new relfilenode */
-	newrelfilenode = GetNewRelFileNode(relation->rd_rel->reltablespace, NULL);
+	newrelfilenode = GetNewRelFileNode(relation->rd_rel->reltablespace, NULL,
+									   relation->rd_backend);
 
 	/*
 	 * Get a writable copy of the pg_class tuple for the given relation.
@@ -2660,9 +2671,10 @@ RelationSetNewRelfilenode(Relation relation, TransactionId freezeXid)
 	 * NOTE: any conflict in relfilenode value will be caught here, if
 	 * GetNewRelFileNode messes up for any reason.
 	 */
-	newrnode = relation->rd_node;
-	newrnode.relNode = newrelfilenode;
-	RelationCreateStorage(newrnode, relation->rd_istemp);
+	newrnode.node = relation->rd_node;
+	newrnode.node.relNode = newrelfilenode;
+	newrnode.backend = relation->rd_backend;
+	RelationCreateStorage(newrnode.node, relation->rd_istemp);
 	smgrclosenode(newrnode);
 
 	/*
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index b209128..77f8cd4 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -96,6 +96,9 @@
 #define MAX_KILOBYTES	(INT_MAX / 1024)
 #endif
 
+/* upper limit for backends - see CacheInvalidateSmgr */
+#define MAX_BACKENDS	0x7fffff
+
 #define KB_PER_MB (1024)
 #define KB_PER_GB (1024*1024)
 
@@ -1415,7 +1418,9 @@ static struct config_int ConfigureNamesInt[] =
 	},
 
 	/*
-	 * Note: MaxBackends is limited to INT_MAX/4 because some places compute
+	 * Note: MaxBackends is limited to 2^23-1 because inval.c stores the
+     * backend ID as a 3-byte signed integer.  Even if that limitation were
+     * removed, we still could not exceed INT_MAX/4 because some places compute
 	 * 4*MaxBackends without any overflow check.  This check is made in
 	 * assign_maxconnections, since MaxBackends is computed as MaxConnections
 	 * plus autovacuum_max_workers plus one (for the autovacuum launcher).
@@ -1430,7 +1435,7 @@ static struct config_int ConfigureNamesInt[] =
 			NULL
 		},
 		&MaxConnections,
-		100, 1, INT_MAX / 4, assign_maxconnections, NULL
+		100, 1, MAX_BACKENDS, assign_maxconnections, NULL
 	},
 
 	{
@@ -1439,7 +1444,7 @@ static struct config_int ConfigureNamesInt[] =
 			NULL
 		},
 		&ReservedBackends,
-		3, 0, INT_MAX / 4, NULL, NULL
+		3, 0, MAX_BACKENDS, NULL, NULL
 	},
 
 	{
diff --git a/src/backend/utils/probes.d b/src/backend/utils/probes.d
index 8ccb948..b06f8ff 100644
--- a/src/backend/utils/probes.d
+++ b/src/backend/utils/probes.d
@@ -55,7 +55,7 @@ provider postgresql {
 	probe sort__done(bool, long);
 
 	probe buffer__read__start(ForkNumber, BlockNumber, Oid, Oid, Oid, bool, bool);
-	probe buffer__read__done(ForkNumber, BlockNumber, Oid, Oid, Oid, bool, bool, bool);
+	probe buffer__read__done(ForkNumber, BlockNumber, Oid, Oid, Oid, int, bool, bool);
 	probe buffer__flush__start(ForkNumber, BlockNumber, Oid, Oid, Oid);
 	probe buffer__flush__done(ForkNumber, BlockNumber, Oid, Oid, Oid);
 
@@ -81,10 +81,10 @@ provider postgresql {
 	probe twophase__checkpoint__start();
 	probe twophase__checkpoint__done();
 
-	probe smgr__md__read__start(ForkNumber, BlockNumber, Oid, Oid, Oid);
-	probe smgr__md__read__done(ForkNumber, BlockNumber, Oid, Oid, Oid, int, int);
-	probe smgr__md__write__start(ForkNumber, BlockNumber, Oid, Oid, Oid);
-	probe smgr__md__write__done(ForkNumber, BlockNumber, Oid, Oid, Oid, int, int);
+	probe smgr__md__read__start(ForkNumber, BlockNumber, Oid, Oid, Oid, int);
+	probe smgr__md__read__done(ForkNumber, BlockNumber, Oid, Oid, Oid, int, int, int);
+	probe smgr__md__write__start(ForkNumber, BlockNumber, Oid, Oid, Oid, int);
+	probe smgr__md__write__done(ForkNumber, BlockNumber, Oid, Oid, Oid, int, int, int);
 
 	probe xlog__insert(unsigned char, unsigned char);
 	probe xlog__switch();
diff --git a/src/include/access/xlog_internal.h b/src/include/access/xlog_internal.h
index 49df96c..e11cce2 100644
--- a/src/include/access/xlog_internal.h
+++ b/src/include/access/xlog_internal.h
@@ -71,7 +71,7 @@ typedef struct XLogContRecord
 /*
  * Each page of XLOG file has a header like this:
  */
-#define XLOG_PAGE_MAGIC 0xD064	/* can be used as WAL version indicator */
+#define XLOG_PAGE_MAGIC 0xD065	/* can be used as WAL version indicator */
 
 typedef struct XLogPageHeaderData
 {
diff --git a/src/include/catalog/catalog.h b/src/include/catalog/catalog.h
index bd430cb..765f571 100644
--- a/src/include/catalog/catalog.h
+++ b/src/include/catalog/catalog.h
@@ -25,10 +25,17 @@
 
 extern const char *forkNames[];
 extern ForkNumber forkname_to_number(char *forkName);
+extern int forkname_chars(const char *str);
 
-extern char *relpath(RelFileNode rnode, ForkNumber forknum);
+extern char *relpathbackend(RelFileNode rnode, BackendId backend,
+			  ForkNumber forknum);
 extern char *GetDatabasePath(Oid dbNode, Oid spcNode);
 
+#define relpath(rnode, forknum) \
+		relpathbackend((rnode).node, (rnode).backend, (forknum))
+#define relpathperm(rnode, forknum) \
+		relpathbackend((rnode), InvalidBackendId, (forknum))
+
 extern bool IsSystemRelation(Relation relation);
 extern bool IsToastRelation(Relation relation);
 
@@ -45,6 +52,7 @@ extern bool IsSharedRelation(Oid relationId);
 extern Oid	GetNewOid(Relation relation);
 extern Oid GetNewOidWithIndex(Relation relation, Oid indexId,
 				   AttrNumber oidcolumn);
-extern Oid	GetNewRelFileNode(Oid reltablespace, Relation pg_class);
+extern Oid	GetNewRelFileNode(Oid reltablespace, Relation pg_class,
+				  BackendId backend);
 
 #endif   /* CATALOG_H */
diff --git a/src/include/catalog/storage.h b/src/include/catalog/storage.h
index 609f1c6..7712d1f 100644
--- a/src/include/catalog/storage.h
+++ b/src/include/catalog/storage.h
@@ -30,8 +30,7 @@ extern void RelationTruncate(Relation rel, BlockNumber nblocks);
  * naming
  */
 extern void smgrDoPendingDeletes(bool isCommit);
-extern int smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr,
-					  bool *haveNonTemp);
+extern int smgrGetPendingDeletes(bool forCommit, RelFileNode **ptr);
 extern void AtSubCommit_smgr(void);
 extern void AtSubAbort_smgr(void);
 extern void PostPrepare_smgr(void);
diff --git a/src/include/postmaster/bgwriter.h b/src/include/postmaster/bgwriter.h
index 06a4e37..a22fbee 100644
--- a/src/include/postmaster/bgwriter.h
+++ b/src/include/postmaster/bgwriter.h
@@ -27,7 +27,7 @@ extern void BackgroundWriterMain(void);
 extern void RequestCheckpoint(int flags);
 extern void CheckpointWriteDelay(int flags, double progress);
 
-extern bool ForwardFsyncRequest(RelFileNode rnode, ForkNumber forknum,
+extern bool ForwardFsyncRequest(BackendRelFileNode rnode, ForkNumber forknum,
 					BlockNumber segno);
 extern void AbsorbFsyncRequests(void);
 
diff --git a/src/include/storage/bufmgr.h b/src/include/storage/bufmgr.h
index f38f545..d4bf341 100644
--- a/src/include/storage/bufmgr.h
+++ b/src/include/storage/bufmgr.h
@@ -160,7 +160,7 @@ extern Buffer ReadBuffer(Relation reln, BlockNumber blockNum);
 extern Buffer ReadBufferExtended(Relation reln, ForkNumber forkNum,
 				   BlockNumber blockNum, ReadBufferMode mode,
 				   BufferAccessStrategy strategy);
-extern Buffer ReadBufferWithoutRelcache(RelFileNode rnode, bool isTemp,
+extern Buffer ReadBufferWithoutRelcache(RelFileNode rnode,
 						  ForkNumber forkNum, BlockNumber blockNum,
 						  ReadBufferMode mode, BufferAccessStrategy strategy);
 extern void ReleaseBuffer(Buffer buffer);
@@ -180,8 +180,8 @@ extern BlockNumber BufferGetBlockNumber(Buffer buffer);
 extern BlockNumber RelationGetNumberOfBlocks(Relation relation);
 extern void FlushRelationBuffers(Relation rel);
 extern void FlushDatabaseBuffers(Oid dbid);
-extern void DropRelFileNodeBuffers(RelFileNode rnode, ForkNumber forkNum,
-					   bool istemp, BlockNumber firstDelBlock);
+extern void DropRelFileNodeBuffers(BackendRelFileNode rnode,
+					   ForkNumber forkNum, BlockNumber firstDelBlock);
 extern void DropDatabaseBuffers(Oid dbid);
 
 #ifdef NOT_USED
diff --git a/src/include/storage/relfilenode.h b/src/include/storage/relfilenode.h
index 6f0c0ad..9bb0fa2 100644
--- a/src/include/storage/relfilenode.h
+++ b/src/include/storage/relfilenode.h
@@ -14,6 +14,8 @@
 #ifndef RELFILENODE_H
 #define RELFILENODE_H
 
+#include "storage/backendid.h"
+
 /*
  * The physical storage of a relation consists of one or more forks. The
  * main fork is always created, but in addition to that there can be
@@ -37,7 +39,8 @@ typedef enum ForkNumber
 
 /*
  * RelFileNode must provide all that we need to know to physically access
- * a relation. Note, however, that a "physical" relation is comprised of
+ * a relation, with the exception of the backend ID, which can be provided
+ * separately. Note, however, that a "physical" relation is comprised of
  * multiple files on the filesystem, as each fork is stored as a separate
  * file, and each fork can be divided into multiple segments. See md.c.
  *
@@ -74,14 +77,30 @@ typedef struct RelFileNode
 } RelFileNode;
 
 /*
- * Note: RelFileNodeEquals compares relNode first since that is most likely
- * to be different in two unequal RelFileNodes.  It is probably redundant
- * to compare spcNode if the other two fields are found equal, but do it
- * anyway to be sure.
+ * Augmenting a relfilenode with the backend ID provides all the information
+ * we need to locate the physical storage.
+ */
+typedef struct BackendRelFileNode
+{
+	RelFileNode	node;
+	BackendId	backend;
+} BackendRelFileNode;
+
+/*
+ * Note: RelFileNodeEquals and BackendRelFileNodeEquals compare relNode first
+ * since that is most likely to be different in two unequal RelFileNodes.  It
+ * is probably redundant to compare spcNode if the other fields are found equal,
+ * but do it anyway to be sure.
  */
 #define RelFileNodeEquals(node1, node2) \
 	((node1).relNode == (node2).relNode && \
 	 (node1).dbNode == (node2).dbNode && \
 	 (node1).spcNode == (node2).spcNode)
 
+#define BackendRelFileNodeEquals(node1, node2) \
+	((node1).node.relNode == (node2).node.relNode && \
+	 (node1).node.dbNode == (node2).node.dbNode && \
+	 (node1).backend == (node2).backend && \
+	 (node1).node.spcNode == (node2).node.spcNode)
+
 #endif   /* RELFILENODE_H */
diff --git a/src/include/storage/sinval.h b/src/include/storage/sinval.h
index bbdde81..d165f4d 100644
--- a/src/include/storage/sinval.h
+++ b/src/include/storage/sinval.h
@@ -26,7 +26,7 @@
  *	* invalidate an smgr cache entry for a specific physical relation
  *	* invalidate the mapped-relation mapping for a given database
  * More types could be added if needed.  The message type is identified by
- * the first "int16" field of the message struct.  Zero or positive means a
+ * the first "int8" field of the message struct.  Zero or positive means a
  * specific-catcache inval message (and also serves as the catcache ID field).
  * Negative values identify the other message types, as per codes below.
  *
@@ -63,7 +63,7 @@
 typedef struct
 {
 	/* note: field layout chosen with an eye to alignment concerns */
-	int16		id;				/* cache ID --- must be first */
+	int8		id;				/* cache ID --- must be first */
 	ItemPointerData tuplePtr;	/* tuple identifier in cached relation */
 	Oid			dbId;			/* database ID, or 0 if a shared relation */
 	uint32		hashValue;		/* hash value of key for this catcache */
@@ -73,7 +73,7 @@ typedef struct
 
 typedef struct
 {
-	int16		id;				/* type field --- must be first */
+	int8		id;				/* type field --- must be first */
 	Oid			dbId;			/* database ID, or 0 if a shared catalog */
 	Oid			catId;			/* ID of catalog whose contents are invalid */
 } SharedInvalCatalogMsg;
@@ -82,7 +82,7 @@ typedef struct
 
 typedef struct
 {
-	int16		id;				/* type field --- must be first */
+	int8		id;				/* type field --- must be first */
 	Oid			dbId;			/* database ID, or 0 if a shared relation */
 	Oid			relId;			/* relation ID */
 } SharedInvalRelcacheMsg;
@@ -91,21 +91,23 @@ typedef struct
 
 typedef struct
 {
-	int16		id;				/* type field --- must be first */
-	RelFileNode rnode;			/* physical file ID */
+	int8		id;				/* type field --- must be first */
+	int8		backend_hi;		/* high bits of backend ID, if temprel */
+	uint16		backend_lo;		/* low bits of backend ID, if temprel */
+	RelFileNode rnode;			/* spcNode, dbNode, relNode */
 } SharedInvalSmgrMsg;
 
 #define SHAREDINVALRELMAP_ID	(-4)
 
 typedef struct
 {
-	int16		id;				/* type field --- must be first */
+	int8		id;				/* type field --- must be first */
 	Oid			dbId;			/* database ID, or 0 for shared catalogs */
 } SharedInvalRelmapMsg;
 
 typedef union
 {
-	int16		id;				/* type field --- must be first */
+	int8		id;				/* type field --- must be first */
 	SharedInvalCatcacheMsg cc;
 	SharedInvalCatalogMsg cat;
 	SharedInvalRelcacheMsg rc;
diff --git a/src/include/storage/smgr.h b/src/include/storage/smgr.h
index cf248b8..7ae78ec 100644
--- a/src/include/storage/smgr.h
+++ b/src/include/storage/smgr.h
@@ -16,6 +16,7 @@
 
 #include "access/xlog.h"
 #include "fmgr.h"
+#include "storage/backendid.h"
 #include "storage/block.h"
 #include "storage/relfilenode.h"
 
@@ -38,7 +39,7 @@
 typedef struct SMgrRelationData
 {
 	/* rnode is the hashtable lookup key, so it must be first! */
-	RelFileNode smgr_rnode;		/* relation physical identifier */
+	BackendRelFileNode smgr_rnode;		/* relation physical identifier */
 
 	/* pointer to owning pointer, or NULL if none */
 	struct SMgrRelationData **smgr_owner;
@@ -68,28 +69,30 @@ typedef struct SMgrRelationData
 
 typedef SMgrRelationData *SMgrRelation;
 
+#define SmgrIsTemp(smgr) \
+	((smgr)->smgr_rnode.backend != InvalidBackendId)
 
 extern void smgrinit(void);
-extern SMgrRelation smgropen(RelFileNode rnode);
+extern SMgrRelation smgropen(RelFileNode rnode, BackendId backend);
 extern bool smgrexists(SMgrRelation reln, ForkNumber forknum);
 extern void smgrsetowner(SMgrRelation *owner, SMgrRelation reln);
 extern void smgrclose(SMgrRelation reln);
 extern void smgrcloseall(void);
-extern void smgrclosenode(RelFileNode rnode);
+extern void smgrclosenode(BackendRelFileNode rnode);
 extern void smgrcreate(SMgrRelation reln, ForkNumber forknum, bool isRedo);
 extern void smgrdounlink(SMgrRelation reln, ForkNumber forknum,
-			 bool isTemp, bool isRedo);
+			 bool isRedo);
 extern void smgrextend(SMgrRelation reln, ForkNumber forknum,
-		   BlockNumber blocknum, char *buffer, bool isTemp);
+		   BlockNumber blocknum, char *buffer, bool skipFsync);
 extern void smgrprefetch(SMgrRelation reln, ForkNumber forknum,
 			 BlockNumber blocknum);
 extern void smgrread(SMgrRelation reln, ForkNumber forknum,
 		 BlockNumber blocknum, char *buffer);
 extern void smgrwrite(SMgrRelation reln, ForkNumber forknum,
-		  BlockNumber blocknum, char *buffer, bool isTemp);
+		  BlockNumber blocknum, char *buffer, bool skipFsync);
 extern BlockNumber smgrnblocks(SMgrRelation reln, ForkNumber forknum);
 extern void smgrtruncate(SMgrRelation reln, ForkNumber forknum,
-			 BlockNumber nblocks, bool isTemp);
+			 BlockNumber nblocks);
 extern void smgrimmedsync(SMgrRelation reln, ForkNumber forknum);
 extern void smgrpreckpt(void);
 extern void smgrsync(void);
@@ -103,27 +106,28 @@ extern void mdinit(void);
 extern void mdclose(SMgrRelation reln, ForkNumber forknum);
 extern void mdcreate(SMgrRelation reln, ForkNumber forknum, bool isRedo);
 extern bool mdexists(SMgrRelation reln, ForkNumber forknum);
-extern void mdunlink(RelFileNode rnode, ForkNumber forknum, bool isRedo);
+extern void mdunlink(BackendRelFileNode rnode, ForkNumber forknum, bool isRedo);
 extern void mdextend(SMgrRelation reln, ForkNumber forknum,
-		 BlockNumber blocknum, char *buffer, bool isTemp);
+		 BlockNumber blocknum, char *buffer, bool skipFsync);
 extern void mdprefetch(SMgrRelation reln, ForkNumber forknum,
 		   BlockNumber blocknum);
 extern void mdread(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum,
 	   char *buffer);
 extern void mdwrite(SMgrRelation reln, ForkNumber forknum,
-		BlockNumber blocknum, char *buffer, bool isTemp);
+		BlockNumber blocknum, char *buffer, bool skipFsync);
 extern BlockNumber mdnblocks(SMgrRelation reln, ForkNumber forknum);
 extern void mdtruncate(SMgrRelation reln, ForkNumber forknum,
-		   BlockNumber nblocks, bool isTemp);
+		   BlockNumber nblocks);
 extern void mdimmedsync(SMgrRelation reln, ForkNumber forknum);
 extern void mdpreckpt(void);
 extern void mdsync(void);
 extern void mdpostckpt(void);
 
 extern void SetForwardFsyncRequests(void);
-extern void RememberFsyncRequest(RelFileNode rnode, ForkNumber forknum,
+extern void RememberFsyncRequest(BackendRelFileNode rnode, ForkNumber forknum,
 					 BlockNumber segno);
-extern void ForgetRelationFsyncRequests(RelFileNode rnode, ForkNumber forknum);
+extern void ForgetRelationFsyncRequests(BackendRelFileNode rnode,
+							ForkNumber forknum);
 extern void ForgetDatabaseFsyncRequests(Oid dbid);
 
 /* smgrtype.c */
diff --git a/src/include/utils/inval.h b/src/include/utils/inval.h
index a86a17c..7fab919 100644
--- a/src/include/utils/inval.h
+++ b/src/include/utils/inval.h
@@ -49,7 +49,7 @@ extern void CacheInvalidateRelcacheByTuple(HeapTuple classTuple);
 
 extern void CacheInvalidateRelcacheByRelid(Oid relid);
 
-extern void CacheInvalidateSmgr(RelFileNode rnode);
+extern void CacheInvalidateSmgr(BackendRelFileNode rnode);
 
 extern void CacheInvalidateRelmap(Oid databaseId);
 
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 444e892..296c651 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -127,7 +127,7 @@ typedef struct RelationData
 	struct SMgrRelationData *rd_smgr;	/* cached file handle, or NULL */
 	int			rd_refcnt;		/* reference count */
 	bool		rd_istemp;		/* rel is a temporary relation */
-	bool		rd_islocaltemp; /* rel is a temp rel of this session */
+	BackendId	rd_backend;		/* owning backend id, if temporary relation */
 	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 =
@@ -347,7 +347,7 @@ typedef struct StdRdOptions
 #define RelationOpenSmgr(relation) \
 	do { \
 		if ((relation)->rd_smgr == NULL) \
-			smgrsetowner(&((relation)->rd_smgr), smgropen((relation)->rd_node)); \
+			smgrsetowner(&((relation)->rd_smgr), smgropen((relation)->rd_node, (relation)->rd_backend)); \
 	} while (0)
 
 /*
@@ -393,7 +393,7 @@ typedef struct StdRdOptions
  * Beware of multiple eval of argument
  */
 #define RELATION_IS_LOCAL(relation) \
-	((relation)->rd_islocaltemp || \
+	((relation)->rd_backend == MyBackendId || \
 	 (relation)->rd_createSubid != InvalidSubTransactionId)
 
 /*
@@ -403,7 +403,7 @@ typedef struct StdRdOptions
  * Beware of multiple eval of argument
  */
 #define RELATION_IS_OTHER_TEMP(relation) \
-	((relation)->rd_istemp && !(relation)->rd_islocaltemp)
+	((relation)->rd_istemp && (relation)->rd_backend != MyBackendId)
 
 /* routines in utils/cache/relcache.c */
 extern void RelationIncrementReferenceCount(Relation rel);