Doctrine\DBAL\Connection::rollbackSavepoint PHP Method

    public function rollbackSavepoint($savepoint)
    {
        if (!$this->getDatabasePlatform()->supportsSavepoints()) {
            throw ConnectionException::savepointsNotSupported();
        }
        $this->_conn->exec($this->platform->rollbackSavePoint($savepoint));
    }

 protected function performRollBack($identifier = NULL)
 {
     if ($identifier === NULL) {
         return $this->conn->rollBack();
     }
     $this->conn->rollbackSavepoint($identifier);
 }