“计划并等待运行”的任务未运行

Question

I have a .net framework 4.6.1 aspnet MVC application which use to work until I updated a number of Nuget packages. I have backed out of most of the key packages and the issue is not fixed. Basically when my application hangs I can see a call to GetListAsync is made and never returns. This is a call to a SQL server using Dapper ORM which I have gone back to a known good version and this does not fix the issue. Looking at the tasks list it would appear to me I have 7 awaiting tasks and 5 tasks which are ready to run but for some reason they are not being scheduled. Looking at my worker ThreadPool I can see I have a good number of threads available and in fact this issue reproduces whenever I just start my aspnet application in dev and there is zero load on the app other than the first request. Any ideas why I would have a number of Scheduled Tasks which never seem to be picked up even if I wait a long period of time?

Answer 1

I faced with this situation when I had a UI thread with

while (true)
{
   var message = await Console.In.ReadLineAsync();
   //some message processing
}

and some of another async methods have been called without await. And I solved this problem with two ways:

Replace all async void to async Task and awaiting all async methods. But this not solved issue with blocking UI thread

And just run

    await Task.Run(async () =>
    {
        while (true)
        {
            var message = await Console.In.ReadLineAsync();
           //some message processing
        }
    }

in another thread.