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Spring Cloud Hystrix線程池不足的解決方法

更新時間：2020年02月05日 14:36:48 作者：drunkery_owner

這篇文章主要介紹了Spring Cloud Hystrix線程池不足的解決方法，文中通過示例代碼介紹的非常詳細(xì)，對大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價值，需要的朋友們下面隨著小編來一起學(xué)習(xí)學(xué)習(xí)吧

現(xiàn)象：

昨天突然線上很多接口獲取失敗，通過 kibana發(fā)現(xiàn)大量異常，具體異常信息：

...into fallback. Rejected command because thread-pool queueSize is at rejection threshold.

異常代碼出處：

@FeignClient(name = "api", fallbackFactory = LoadBalancingFallbackFactory.class)
public interface LoadBalancingFeignClient {

  @PostMapping(value = "/api/loadBalancing/server")
  Result currentServer();

}

@Slf4j
@Component
public class LoadBalancingFallbackFactory implements FallbackFactory<LoadBalancingFeignClient> {

  @Override
  public LoadBalancingFeignClient create(Throwable throwable) {
    final String msg = throwable.getMessage();
    return () -> {
      log.error("loadBalancingFeignClient currentServer into fallback. {}", msg);
      return Result.error();
    };****
  }

}

原因：

看到這里已經(jīng)很明顯了，是由于hystrix線程池不夠用，直接熔斷導(dǎo)致的。
項(xiàng)目apollo配置：

hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds = 3500
hystrix.threadpool.default.maxQueueSize = 60
hystrix.threadpool.default.queueSizeRejectionThreshold = 40

hystrix參數(shù)簡析：

maxQueueSize：線程池大小，默認(rèn)為-1，創(chuàng)建的隊(duì)列是SynchronousQueue，如果設(shè)置大于0則根據(jù)其大小創(chuàng)建LinkedBlockingQueue。

queueSizeRejectionThreshold：動態(tài)控制線程池隊(duì)列的上限，即使maxQueueSize沒有達(dá)到，達(dá)到queueSizeRejectionThreshold該值后，請求也會被拒絕，默認(rèn)值5

相關(guān)源碼：

hystrix-core-1.5.12-sources.jar!/com/netflix/hystrix/strategy/concurrency/HystrixContextScheduler.java

  private class HystrixContextSchedulerWorker extends Worker {

    private final Worker worker;

    private HystrixContextSchedulerWorker(Worker actualWorker) {
      this.worker = actualWorker;
    }

    @Override
    public void unsubscribe() {
      worker.unsubscribe();
    }

    @Override
    public boolean isUnsubscribed() {
      return worker.isUnsubscribed();
    }

    @Override
    public Subscription schedule(Action0 action, long delayTime, TimeUnit unit) {
      if (threadPool != null) {
        if (!threadPool.isQueueSpaceAvailable()) {
          throw new RejectedExecutionException("Rejected command because thread-pool queueSize is at rejection threshold.");
        }
      }
      return worker.schedule(new HystrixContexSchedulerAction(concurrencyStrategy, action), delayTime, unit);
    }

    @Override
    public Subscription schedule(Action0 action) {
      if (threadPool != null) {
        if (!threadPool.isQueueSpaceAvailable()) {
          throw new RejectedExecutionException("Rejected command because thread-pool queueSize is at rejection threshold.");
        }
      }
      return worker.schedule(new HystrixContexSchedulerAction(concurrencyStrategy, action));
    }

  }

解決辦法：