private function doPopMessage($queueName)
    {
        $query = 'SELECT id, message FROM bernard_messages
                  WHERE queue = :queue AND visible = :visible
                  ORDER BY sentAt LIMIT 1 '.$this->connection->getDatabasePlatform()->getForUpdateSql();

        list($id, $message) = $this->connection->fetchArray($query, [
            'queue' => $queueName,
            'visible' => true,
        ]);

        if ($id) {
            $this->connection->update('bernard_messages', ['visible' => 0], compact('id'));

            return [$message, $id];
        }
    }