diff --git a/internal/storage/binlog_iterator.go b/internal/storage/binlog_iterator.go
index 7ce87b2900..061caaf284 100644
--- a/internal/storage/binlog_iterator.go
+++ b/internal/storage/binlog_iterator.go
@@ -21,7 +21,7 @@ import (
 var (
 	// ErrNoMoreRecord is the error that the iterator does not have next record.
 	ErrNoMoreRecord = errors.New("no more record")
-	// ErrDisposed is the error that the iterator is disposed
+	// ErrDisposed is the error that the iterator is disposed.
 	ErrDisposed = errors.New("iterator is disposed")
 )