diff --git a/dumpling/v4/export/sql.go b/dumpling/v4/export/sql.go
index 655d9c2b8a571..d40b4a1e78203 100644
--- a/dumpling/v4/export/sql.go
+++ b/dumpling/v4/export/sql.go
@@ -967,7 +967,7 @@ func parseSnapshotToTSO(pool *sql.DB, snapshot string) (uint64, error) {
 	if !tso.Valid {
 		return 0, errors.Errorf("snapshot %s format not supported. please use tso or '2006-01-02 15:04:05' format time", snapshot)
 	}
-	return (uint64(tso.Int64)<<18)*1000 + 1, nil
+	return (uint64(tso.Int64) << 18) * 1000, nil
 }
 
 func buildWhereCondition(conf *Config, where string) string {
diff --git a/dumpling/v4/export/sql_test.go b/dumpling/v4/export/sql_test.go
index 7d8c94addb59c..5689f3ee15584 100644
--- a/dumpling/v4/export/sql_test.go
+++ b/dumpling/v4/export/sql_test.go
@@ -317,7 +317,7 @@ func (s *testSQLSuite) TestParseSnapshotToTSO(c *C) {
 		WillReturnRows(sqlmock.NewRows([]string{`unix_timestamp("2020/07/18 20:31:50")`}).AddRow(1595075510))
 	tso, err := parseSnapshotToTSO(db, snapshot)
 	c.Assert(err, IsNil)
-	c.Assert(tso, Equals, (unixTimeStamp<<18)*1000+1)
+	c.Assert(tso, Equals, (unixTimeStamp<<18)*1000)
 	c.Assert(mock.ExpectationsWereMet(), IsNil)
 
 	// generate columns not valid snapshot