diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index f3e7018ed2..aa338e880c 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -3868,12 +3868,24 @@ generate_partitionwise_join_paths(PlannerInfo *root, RelOptInfo *rel)
 		if (child_rel == NULL)
 			continue;
 
-		/* Add partitionwise join paths for partitioned child-joins. */
+		/* Make partitionwise join paths for this partitioned child-join. */
 		generate_partitionwise_join_paths(root, child_rel);
 
+		/* If we failed to make any path for this child, we must give up. */
+		if (child_rel->pathlist == NIL)
+		{
+			/*
+			 * Mark the parent joinrel as unpartitioned so that later
+			 * functions treat it correctly.
+			 */
+			rel->nparts = 0;
+			return;
+		}
+
+		/* Else, identify the cheapest path for it. */
 		set_cheapest(child_rel);
 
-		/* Dummy children will not be scanned, so ignore those. */
+		/* Dummy children need not be scanned, so ignore those. */
 		if (IS_DUMMY_REL(child_rel))
 			continue;