diff --git a/src/bin/pg_upgrade/pg_upgrade.h b/src/bin/pg_upgrade/pg_upgrade.h
index 92bcb693fbf..8afe240bdfb 100644
--- a/src/bin/pg_upgrade/pg_upgrade.h
+++ b/src/bin/pg_upgrade/pg_upgrade.h
@@ -321,8 +321,7 @@ typedef struct
 */
 typedef struct
 {
-	bool		check;			/* true -> ask user for permission to make
-								 * changes */
+	bool		check;			/* check clusters only, don't change any data */
 	bool		do_sync;		/* flush changes to disk */
 	transferMode transfer_mode; /* copy files or link them? */
 	int			jobs;			/* number of processes/threads to use */