diff --git a/src/backend/statistics/attribute_stats.c b/src/backend/statistics/attribute_stats.c
index e65c8dac4a4..5649d01ebe7 100644
--- a/src/backend/statistics/attribute_stats.c
+++ b/src/backend/statistics/attribute_stats.c
@@ -249,8 +249,8 @@ attribute_statistics_update_internal(Oid reloid,
 	bool		result = true;
 
 	/*
-	 * Check argument sanity. If some arguments are unusable, emit a WARNING
-	 * and set the corresponding argument to NULL in fcinfo.
+	 * Check argument sanity.  If some arguments are unusable, emit a WARNING
+	 * and skip the corresponding statistics kind, reporting back a failure.
 	 */
 
 	if (!stats_check_arg_array(fcinfo, attarginfo, MOST_COMMON_FREQS_ARG))