diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 62aeb2f3e6a..3c7bc2a56b9 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.266 2008/09/08 00:47:40 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/tablecmds.c,v 1.267 2008/10/07 11:15:41 heikki Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -6488,6 +6488,7 @@ ATExecSetTableSpace(Oid tableOid, Oid newTableSpace)
 	Oid			oldTableSpace;
 	Oid			reltoastrelid;
 	Oid			reltoastidxid;
+	Oid			newrelfilenode;
 	RelFileNode newrnode;
 	SMgrRelation dstrel;
 	Relation	pg_class;
@@ -6557,8 +6558,17 @@ ATExecSetTableSpace(Oid tableOid, Oid newTableSpace)
 	 */
 	FlushRelationBuffers(rel);
 
+	/*
+	 * Relfilenodes are not unique across tablespaces, so we need to allocate
+	 * a new one in the new tablespace.
+	 */
+	newrelfilenode = GetNewRelFileNode(newTableSpace,
+									   rel->rd_rel->relisshared,
+									   NULL);
+
 	/* Open old and new relation */
 	newrnode = rel->rd_node;
+	newrnode.relNode = newrelfilenode;
 	newrnode.spcNode = newTableSpace;
 	dstrel = smgropen(newrnode);
 
@@ -6588,6 +6598,7 @@ ATExecSetTableSpace(Oid tableOid, Oid newTableSpace)
 
 	/* update the pg_class row */
 	rd_rel->reltablespace = (newTableSpace == MyDatabaseTableSpace) ? InvalidOid : newTableSpace;
+	rd_rel->relfilenode = newrelfilenode;
 	simple_heap_update(pg_class, &tuple->t_self, tuple);
 	CatalogUpdateIndexes(pg_class, tuple);