func (tx *writableSqlTx) rollbackToSavepoint() error {
    if sqlLgr.IsDebugEnabled() {
        sqlLgr.Debug().Str("db_name", tx.litetree.name).Msg("rollback to savepoint")
    }
    _, err := tx.Tx.Exec("ROLLBACK TO SAVEPOINT \"" + tx.litetree.name + "\"")