diff --git a/src/port/pqsignal.c b/src/port/pqsignal.c
index 5dd8b76bae8..79b50486175 100644
--- a/src/port/pqsignal.c
+++ b/src/port/pqsignal.c
@@ -87,6 +87,8 @@ wrapper_handler(SIGNAL_ARGS)
 {
 	int			save_errno = errno;
 
+	Assert(postgres_signal_arg < PG_NSIG);
+
 #ifndef FRONTEND
 
 	/*