diff --git a/internal/gridcache/gridcache.go b/internal/gridcache/gridcache.go
index b96646d..434854d 100644
--- a/internal/gridcache/gridcache.go
+++ b/internal/gridcache/gridcache.go
@@ -186,6 +186,10 @@ func (s *Store) Flush() error {
 		s.requeue(batch)
 		return err
 	}
+	// Logged because a batch that never reaches the disk looks exactly like one
+	// that does: the locators are in memory either way until the next restart,
+	// which is the one moment the difference shows.
+	s.logf("gridcache: wrote %d locators", len(batch))
 	return nil
 }