public function getInitialPagesAdditionalWhereClause($configurationName)
    {
        $path = 'plugin.tx_solr.index.queue.' . $configurationName . '.initialPagesAdditionalWhereClause';
        $initialPagesAdditionalWhereClause = $this->getValueByPathOrDefaultValue($path, '');

        if (trim($initialPagesAdditionalWhereClause) === '') {
            return '';
        }

        return trim($initialPagesAdditionalWhereClause);
    }