diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index d5a10adc67..e3b0cbb708 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -30,6 +30,7 @@
 #include "miscadmin.h"
 #include "parser/parse_relation.h"
 #include "rewrite/rewriteHandler.h"
+#include "storage/lmgr.h"
 #include "storage/smgr.h"
 #include "tcop/tcopprot.h"
 #include "utils/builtins.h"
@@ -240,9 +241,14 @@ ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
 
 	heap_close(matviewRel, NoLock);
 
-	/* Create the transient table that will receive the regenerated data. */
+	/*
+	 * Create the transient table that will receive the regenerated data.
+	 * Lock it against access by any other process until commit (by which time
+	 * it will be gone).
+	 */
 	OIDNewHeap = make_new_heap(matviewOid, tableSpace, concurrent,
 							   ExclusiveLock);
+	LockRelationOid(OIDNewHeap, AccessExclusiveLock);
 	dest = CreateTransientRelDestReceiver(OIDNewHeap);
 
 	/* Generate the data, if wanted. */