I would like to handle 3.000 requests per second via proxy usage.

The following code without proxy works without problems and can handle 3.000 requests per second with an average send-response time of ~50MS per request:

Http(context.system)
  .singleRequest(request) // live without proxies -> speed boost by over 100%
  .flatMap(_.toStrict(2.seconds)) // locally it might take longer than 2 seconds
  .flatMap { resp =>
    Unmarshal(resp.entity).to[String].map((resp.status, _)) 
  }

---

But now I would like to archive the same but via Proxy usage:

val httpsProxyTransport = ClientTransport.httpsProxy(InetSocketAddress.createUnresolved("proxyip", 8888))
val settings: ConnectionPoolSettings = ConnectionPoolSettings(context.system)
                  .withTransport(httpsProxyTransport)
                  .withMaxRetries(0)
                  .withMaxConnectionBackoff(2.seconds) 

Http(context.system)
    .singleRequest(request, settings = settings) 
    .flatMap(_.toStrict(2.seconds)) 
    .flatMap { resp =>
      Unmarshal(resp.entity).to[String].map((resp.status, _)) 
    }

Problem is that the proxy version:

• 1.000 requests / second -> average send-response time of ~50MS per request just like the solution without proxy
• 1.500 requests / second -> average send-response time of ~80MS per request
• 2.000 requests / second -> average send-response time of ~150MS per request

The proxy version gets worse in terms of average response time the more I try to send through. I doubt the problems lies on the end of the proxy, as I've also tried to use 3 different proxies at the same time to balance like 1.000 requests per proxy, but it showed the same increase in average response time.

Any ideas, what could under the hood limit the https proxy requests?

(It feels kind of as if the proxy version isn't using multiple cores in parallel.)

---

host-connection-pool {   
  max-connections = 650
  max-retries = 0
  max-open-requests = 1024  
  idle-timeout = 5 s
}

---

dispatcher-io {
  type = Dispatcher
  executor = "thread-pool-executor"
  thread-pool-executor {
    fixed-pool-size = 350  
    keep-alive-time = 60s
    allow-core-timeout = on
  }
  shutdown-timeout = 60s
  throughput = 1
}

---