Из-за чего может в GearmanClient::ping периодически срабатывать exception GEARMAN_TIMEOUT?

Question

[zshurick]

Возникающая ошибка:

Gearman not connected, check it, GearmanClient::ping(): send_packet(GEARMAN_TIMEOUT) Failed in receiving() -> libgearman/connection.cc:399 in /,,,/:19

try {

            $echo_data = $this->client->ping('test_string');

            if($echo_data === FALSE){
                Log::instance()->add(Log::CRITICAL, 'Gearman not connected, check it')
                          ->write();
                return false;
            }

        }catch (Exception $e){
            Log::instance()->add(Log::CRITICAL, 'Gearman not connected, check it, :error',
                    array(':error'=>$e->getMessage()));
            return false;
        }
}