public function countOpenByIdentifier($identifier): int
    {
        $queryBuilder = $this->createQuery();
        $where = $queryBuilder->expr()->andX(
            $queryBuilder->expr()->eq('cache_url', $queryBuilder->createNamedParameter($identifier)),
            $queryBuilder->expr()->eq('call_date', $queryBuilder->createNamedParameter(0))
        );

        return (int)$queryBuilder->select('uid')
            ->from($this->getTableName())
            ->where($where)
            ->execute()
            ->rowCount();
    }