diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index b04dc2ed49e..662b97755ab 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -71,6 +71,7 @@ static List *build_index_tlist(PlannerInfo *root, IndexOptInfo *index,
  *	min_attr	lowest valid AttrNumber
  *	max_attr	highest valid AttrNumber
  *	indexlist	list of IndexOptInfos for relation's indexes
+ *	serverid	if it's a foreign table, the server OID
  *	fdwroutine	if it's a foreign table, the FDW function pointers
  *	pages		number of pages
  *	tuples		number of tuples