diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index c0d3fb84911..0dfb1b4a6a0 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -350,7 +350,7 @@
 #join_collapse_limit = 8		# 1 disables collapsing of explicit
 					# JOIN clauses
 #force_parallel_mode = off
-#plan_cache_mode = auto
+#plan_cache_mode = auto			# auto, force_generic_plan or force_custom_plan
 
 
 #------------------------------------------------------------------------------