diff --git a/src/backend/executor/execPartition.c b/src/backend/executor/execPartition.c
index 75329b3624..da962c4375 100644
--- a/src/backend/executor/execPartition.c
+++ b/src/backend/executor/execPartition.c
@@ -975,7 +975,7 @@ get_partition_dispatch_recurse(Relation rel, Relation parent,
 	 * array element belongs to a leaf partition or a subpartitioned table.
 	 * For leaf partitions we store the 0-based index into *leaf_part_oids,
 	 * and for sub-partitioned tables we store a negative version of the
-	 * 1-based index into the *pds list.  When searching, if we see a negative
+	 * 0-based index into the *pds list.  When searching, if we see a negative
 	 * value, the search must continue in the corresponding sub-partition;
 	 * otherwise, we've identified the correct partition.
 	 */
@@ -986,8 +986,8 @@ get_partition_dispatch_recurse(Relation rel, Relation parent,
 
 		if (get_rel_relkind(partrelid) != RELKIND_PARTITIONED_TABLE)
 		{
+			pd->indexes[i] = list_length(*leaf_part_oids);
 			*leaf_part_oids = lappend_oid(*leaf_part_oids, partrelid);
-			pd->indexes[i] = list_length(*leaf_part_oids) - 1;
 		}
 		else
 		{