Unable to set Socket Timeout less than 1000 milliseconds in RequestConfig (Apache HTTP async client 4.1.2)

Question

Following is my code

       RequestConfig requestConfig = RequestConfig.custom()
                .setSocketTimeout(100)
                .setConnectTimeout(100)
                .setConnectionRequestTimeout(100).build();


        CloseableHttpAsyncClient httpClient = HttpAsyncClients.custom()
                .setDefaultRequestConfig(requestConfig)
                .build();

        httpClient.start();

According to setSocketTimeout value, it should timeout in 100 ms, but it is taking 1000 ms to timeout. setSocketTimeout is honouring all value greater than 1000 ms, though.

Sarilda

100ms is far too short for a read timeout or a connect timeout. – Titleholder

@EJP 1000 ms seems to be minimum value allowed for socket timeout. Any value less than 1000 ms is being set as 1000. – Sarilda

By this framework. Not by Java. – Titleholder

Answer 1

This behavior is intentional. The i/o selector threads need to iterate over existing i/o sessions on a regular basis and trigger socket timeout event in case of i/o inactivity. This operation can get very expensive especially as the number of concurrent sessions grows. By default the i/o select interval is set to 1000 ms, and therefore the granularity of socket timeout by default is 1 sec. One can reduce the select interval and make i/o selector threads iterate over sessions more often at the cost of greater CPU utilization. With select interval of 1ms i/o selector threads will effectively run in a busy loop.

IOReactorConfig ioReactorConfig = IOReactorConfig.custom()
        .setSelectInterval(100)
        .setSoTimeout(100)
        .setConnectTimeout(100)
        .build();
CloseableHttpAsyncClient httpClient = HttpAsyncClients.custom()
        .setDefaultIOReactorConfig(ioReactorConfig)
        .build();

Demagogy