diff --git a/sync/sync0sync.c b/sync/sync0sync.c
index 8c65a9875f71459a4c761e8a42e1da7ef0539640..94f1269c149d3554beb9e4374806f51006f0e6a2 100644
--- a/sync/sync0sync.c
+++ b/sync/sync0sync.c
@@ -1039,7 +1039,7 @@ sync_thread_add_level(
 		if (!sync_thread_levels_g(array, level)) {
 			fprintf(stderr,
 				"InnoDB: sync_thread_levels_g(array, %lu)"
-				"does not hold!\n", level);
+				" does not hold!\n", level);
 			ut_error;
 		}
 		break;