diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c
index c4422fe9860a4e21f97be27e71991e64fcad5ebd..1c20edcdfeb2a348dd8cce66f19c0320d8bc9247 100644
--- a/src/backend/optimizer/path/costsize.c
+++ b/src/backend/optimizer/path/costsize.c
@@ -263,7 +263,7 @@ cost_seqscan(Path *path, PlannerInfo *root,
 		 * because they'll anticipate receiving more rows than any given copy
 		 * will actually get.
 		 */
-		path->rows /= parallel_divisor;
+		path->rows = clamp_row_est(path->rows / parallel_divisor);
 
 		/* The CPU cost is divided among all the workers. */
 		cpu_run_cost /= parallel_divisor;