HyperV环境中AsyncController的TimeoutException

Question

我们在Beta HyperV环境中的MVC AsyncController上获得了TimeoutException.在本地调试时一切正常,但是当我们部署到预生产环境时,我们收到此错误:

[TimeoutException:操作已超时.] System.Web.Mvc.Async.WrappedAsyncResult`1.End()+129 System.Web.Mvc.Async.<> c_ DisplayClass39.b _38(IAsyncResult asyncResult)+23 System. Web.Mvc.Async.<> c_ DisplayClass33.b _2d()+ 125 System.Web.Mvc.Async.<> c_ DisplayClass49.b _43()+452 System.Web.Mvc.Async.<> c_ DisplayClass49.b _43()+452 System.Web.Mvc.Async.<> c_ DisplayClass49.b _43()+452 System.Web.Mvc.Async.<> c_ DisplayClass31.b _30(IAsyncResult asyncResult)+15 System.Web.Mvc .Async.<> c_ DisplayClass24.b _1a()+31 System.Web.Mvc.Async.<> c_ DisplayClass1f.b _1c(IAsyncResult asyncResult)+230 System.Web.Mvc.<> c_DisplayClass17.b _12(IAsyncResult asyncResult)+28 System.Web.Mvc.Async.<> c_ DisplayClass4.b _3(IAsyncResult ar)+20 System.Web.Mvc.AsyncController.EndExecuteCore(IAsyncResult asyncResult)+53 System.Web. Mvc.Async.<> c_ DisplayClass4.b _3(IAsyncResult ar)+20 System.Web.Mvc.<> c_ DisplayClass8.b _3(IAsyncResult asyncResult)+42 System.Web.Mvc.Async.<> c_ DisplayClass4.b _3(IAsyncResult ar)+20 System.Web.CallHandlerExecutionStep.OnAsyncHandlerCompletion(IAsyncResult ar)+136

    [OutputCache(Duration = 0, NoStore = true, VaryByParam = "")]
            public void IndexAsync()
            {
                using (var context = Repository.CreateContext().CreateUnitOfWork())
                {
                    user = context.Users.Single(u => u.Username == User.Identity.Name);

                        AsyncManager.OutstandingOperations.Increment();

                        ThreadPool.QueueUserWorkItem(o => {
                            var sync = myService.DoThingsAsync(user);
                            sync.AsyncWaitHandle.WaitOne();
                            AsyncManager.OutstandingOperations.Decrement();  
                        });
                }
            }

/// IndexCompleted is never called
     public ActionResult IndexCompleted(string property)
            {
                using (var context = Repository.CreateContext().CreateUnitOfWork())
                {
                    var user = context.Users.Single(u => u.Username == User.Identity.Name);

                    var model = new MyViewModel
                    {
                        ModelProperty = user.Property
                    };

                    return View("Index", model);
                }
            }

导致此错误的可能原因是什么？

Answer 1

这是异步操作所花费的时间超过配置的AsyncTimeout值(默认为45秒)时抛出的异常.您可以通过使用AsyncTimeout属性修饰ActionMethod来显式控制此值.例如,要将异步超时设置为整分钟:

[AsyncTimeout(60000)]
public void IndexAsync()
{
   ...
}

您还可以使用NoAsyncTimeout属性,但是您将容易受到异常操作的影响,这些操作永远不会完成,并且会使您的Web请求处于不稳定状态.