protected function getMasterConnection()
    {
        $db_config = $this->containers['config']->get('mysql');
        $master_db_config = $db_config['master'];
        $this->_master_db = isset($master_db_config['dbname']) ? $master_db_config['dbname'] : '';
        $this->_master_host = isset($master_db_config['host']) ? $master_db_config['host'] : '';
        $this->_master_username = isset($master_db_config['username']) ? $master_db_config['username'] : '';
        $this->_master_password = isset($master_db_config['password']) ? $master_db_config['password'] : '';
        $this->_master_options = isset($master_db_config['options']) ? $master_db_config['options'] : [];
        $this->getDsn(self::CONN_TYPE_MASTER);
        $this->getConnection(self::CONN_TYPE_MASTER);
    }