diff --git a/src/backend/access/nbtree/nbtinsert.c b/src/backend/access/nbtree/nbtinsert.c
index 6ac205c98e..c9d3fc81a6 100644
--- a/src/backend/access/nbtree/nbtinsert.c
+++ b/src/backend/access/nbtree/nbtinsert.c
@@ -104,7 +104,7 @@ _bt_doinsert(Relation rel, IndexTuple itup,
 	BTInsertStateData insertstate;
 	BTScanInsert itup_key;
 	BTStack		stack;
-	bool		checkingunique = (checkUnique != UNIQUE_CHECK_NO);
+	bool		checkingunique = (!indexUnchanged && checkUnique != UNIQUE_CHECK_NO);
 
 	/* we need an insertion scan key to do our search, so build one */
 	itup_key = _bt_mkscankey(rel, itup);