public function prepareForNextAttempt($job_id, $previous_attempts, $delay = 0)
    {
        $this->connection->execute('UPDATE `' . self::JOBS_TABLE_NAME . '` SET `available_at` = ?, `reservation_key` = NULL, `reserved_at` = NULL, `attempts` = ? WHERE `id` = ?', date('Y-m-d H:i:s', time() + $delay), $previous_attempts + 1, $job_id);
    }