PoolingHttpClientConnectionManager setMaxTotal or setDefaultMaxPerRoute don't seem to work

Question

In a spring boot application, I am creating a connection pool using PoolingHttpClientConnectonManager as follows:

      @Bean
      public PoolingHttpClientConnectionManager createCM() {
        PoolingHttpClientConnectionManager pcm = new PoolingHttpClientConnectionManager();
        poolingHttpClientConnectionManager.setMaxTotal(100);
        poolingHttpClientConnectionManager.setDefaultMaxPerRoute(100);
        return pcm;
      }

Since I have only one route, I keep the values of setMaxTotal and setDefaultMaxPerRoute same.

The underlying httpClient configuration is as follows:

      @Bean
      public CloseableHttpClient createHttpClient(PoolingHttpClientConnectionManager pcm, RequestConfig rc) {

          CloseableHttpClient httpClient = HttpClientBuilder
          .create()
          .setConnectionManager(pcm)
          .setDefaultRequestConfig(rc)
          .build();
        return httpClient;
      }

Now the problem is that when I stress test my application under very heavy loads to see how my connection pool would behave, I don't see the expected. I monitor the threads of the application using jConsole and every single time I see only 2 connection pool threads in runnable state namely https-jsse-nio-80-ClientPoller-1 and https-jsse-nio-80-ClientPoller-2.

I presume under heavy loads of the order of 1500 requests per second, it should have done it by more than 2 (default) connections in the pool. wondering what's going wrong or if my configuration is not correct.

Answer 1

In my case I'm using http component as soap client library and I use a class implementing WebServiceGatewaySupport. On this i do as follows:

httpComponentsRequestFactory = new HttpComponentsClientHttpRequestFactory();
httpComponentsRequestFactory.setReadTimeout(readTimeout);
httpComponentsRequestFactory.setConnectTimeout(connectionTimeout);
httpComponentsRequestFactory.setHttpClient(createHttpClient(createConnectionManager(), createRequestConfig()));
client.setMessageSender(new ClientHttpRequestMessageSender(httpComponentsRequestFactory));

and enabling logging to level DEBUG for org.apache.http I see now:

Connection released: [id: 0][route: {}->http://host:8080][total available: 1; route allocated: 1 of 100; total allocated: 1 of 100]

so I manged to rise the default to 100 connections.