$this->_getClient()->init($metadata->getTableName());

public function init($name)
{
    $tableName = $this->_factory->getSingleton('core/resource')->getTableName($name);
    $this->_metadata = $this->_factory->getModel('enterprise_mview/metadata')
        ->load($tableName, 'table_name');
    if (!$this->_metadata->getId()) {
        $this->_metadata->setTableName($tableName);
    }
    return $this;
}

public function initByTableName($tableName)
{
    $this->_metadata = $this->_factory->getModel('enterprise_mview/metadata')
        ->load($tableName, 'table_name');
    if (!$this->_metadata->getId()) {
        $this->_metadata->setTableName($tableName);
    }
    return $this;
}

protected function _runCleanupAction(Enterprise_Mview_Model_Metadata $metadata)
{
    $this->_getClient()->initByTableName($metadata->getTableName());
    try {
        $this->_getClient()->execute('enterprise_mview/action_changelog_clear');
    } catch (Exception $e) {
        $this->_logger->logException($e);
    }
}