diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index a555b7b2508..ad9d6338ec2 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -1077,7 +1077,7 @@ continue_page:
 			ItemId		lpp;
 			OffsetNumber lineoff;
 
-			Assert(lineindex <= scan->rs_ntuples);
+			Assert(lineindex < scan->rs_ntuples);
 			lineoff = scan->rs_vistuples[lineindex];
 			lpp = PageGetItemId(page, lineoff);
 			Assert(ItemIdIsNormal(lpp));