我的代码中的并行性可能导致"等待来自池的连接超时"

Question

我有这个java http客户端代码：

 private void init(String[] args) {
        setServerVersion(args);
        commonParallelGenerator.setInputFlavor();
        commonParallelGenerator.setNumberOfThreads("25"); //machine has 31 cores.
    }

...

            Report report = requestsList
                    .parallelStream()
                    .map(request -> freshResultsGenerator.getResponse(request, e2EResultLongBL))
...

/

/最终使用此 http 客户端：

import org.apache.http.StatusLine;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.util.EntityUtils;
import org.apache.log4j.Logger;
import com.google.common.base.Stopwatch;
import com.google.common.base.Strings;
import com.google.inject.Inject;

public class RoutingUrlHttpClient implements IRoutingUrlHttpClient {
    final static Logger logger = Logger.getLogger(RoutingUrlHttpClient.class);

    private IRoutingResponseFromStringFetcher routingResponseParser;
    private IRoutingResponseConverter routingResponseConverter;
    private IUrlUtils urlUtils;
    private CloseableHttpClient client;
    private ILogUtils logUtils;

    @Inject
    @Singleton
    public RoutingUrlHttpClient(IRoutingResponseFromStringFetcher routingResponseParser,
                                IRoutingResponseConverter routingResponseConverter, IUrlUtils urlUtils,
                                ILogUtils logUtils) {
        this.routingResponseParser = routingResponseParser;
        this.routingResponseConverter = routingResponseConverter;
        this.urlUtils = urlUtils;
        this.logUtils = logUtils;
        RequestConfig requestConfig = RequestConfig.custom()
                //time till handshake
                .setConnectTimeout(40 * 1000)
                //happens when you have a pool of connections and they are all busy, not allowing the connection
                // manager to give you one connection to make the request.
                .setConnectionRequestTimeout(40 * 1000)
                //time till response
                .setSocketTimeout(40 * 1000)
                .build();
        client = HttpClientBuilder
                .create()
                .setDefaultRequestConfig(requestConfig)
                .build();
    }
    private CompleteRoutingResponseDtoWrapper sendRoutingRequestString(int numberOfTriesLeft,
                                                                       String routingRequestUrl) {
        routingRequestUrl = urlUtils.getHttpUrl(routingRequestUrl);
        CompleteRoutingResponseDtoWrapper answer = new CompleteRoutingResponseDtoWrapper();
        CloseableHttpResponse response = null;
        try {
            logger.debug("before sending http");
            Stopwatch stopWatch = Stopwatch.createStarted();
            response = client.execute(new HttpGet(routingRequestUrl));
            stopWatch.stop();
//            String latencyMsg = "after sending http. client-latency: "+stopWatch.elapsed(TimeUnit.MILLISECONDS) +" server-latency: "+response.getHeaders("Latency")[0].getValue();
            logUtils.addLongToLongStatisticCollector("http.client.latency", (int)stopWatch.elapsed(TimeUnit.MILLISECONDS));
            logUtils.addLongToLongStatisticCollector("http.server.latency", Integer.parseInt(response.getHeaders("Latency")[0].getValue()));
            answer = analyzeStatusCodeAndMsgBody(numberOfTriesLeft, routingRequestUrl, answer, response, stopWatch);

        } catch (Exception e) {
//            e.printStackTrace();
//            System.out.println(e.getMessage());
            answer.errorMsg = e.getMessage();
            answer.latency = null;
        }
        handleNullResponse(answer);
        return answer;
    }

我经常收到错误：

Timeout waiting for connection from pool

当我收到来自这个想法的请求时，

但是当我导航抛出浏览器时导航效果很好

你认为我应该在哪里调查瓶颈？

Answer 1

问题是我没有关闭 httpClient

            //try-with-resources
            try (CloseableHttpClient client = HttpClientBuilder
                    .create()
                    .setDefaultRequestConfig(requestConfig)
                    .build()){
                response = client.execute(new HttpGet(routingRequestUrl));
            stopWatch.stop();
//            String latencyMsg = "after sending http. client-latency: "+stopWatch.elapsed(TimeUnit.MILLISECONDS) +" server-latency: "+response.getHeaders("Latency")[0].getValue();
            logUtils.addLongToLongStatisticCollector("http.client.latency", (int)stopWatch.elapsed(TimeUnit.MILLISECONDS));
            logUtils.addLongToLongStatisticCollector("http.server.latency", Integer.parseInt(response.getHeaders("Latency")[0].getValue()));
            answer = analyzeStatusCodeAndMsgBody(numberOfTriesLeft, routingRequestUrl, answer, response, stopWatch);
            }

Answer 2

关闭客户端可以解决问题，但是如果您在每次调用后关闭客户端，则不会重复使用连接，也不会使用连接池。

我宁愿确保您关闭 HttpResponse，它将连接返回到池中。

    try (CloseableHttpResponse response = client2.execute(get))
    {
        response.getStatusLine();
        // ..... read response and such
    }

有关更多详细信息，请参阅 https://hc.apache.org/httpcomponents-client-ga/tutorial/html/connmgmt.html。

当然，您必须小心池配置，因为默认配置默认情况下每个路由仅设置 2 个连接（这可能有点低）。