Using Task or async/await in IHttpAsyncHandler

Question

Since the very begining of writing ASP.NET applications when I wanted to add a threading there are 3 simple ways I can accomplish threading within my ASP.NET application :

Answer 1

Another thing to consider is that async/await and TPL (Task) are not the same thing.

Please read this excellent post http://blogs.msdn.com/b/ericlippert/archive/2010/11/04/asynchrony-in-c-5-0-part-four-it-s-not-magic.aspx to understand why async/await doesn't mean "using a background thread".

Going back to our topic here, in your particular case where you want to perform some expensive calculations inside an AsyncHandler you have three choices:

1) leave the code inside the Asynchandler so the expensive calculation will use the current thread from the ThreadPool. 2) run the expensive calculation code in another ThreadPool thread by using Task.Run or a Delegate 3) Run the expensive calculation code in another thread from your custom thread pool (or IOCP threadPool).

The second case MIGHT be enough for you depending on how long your "calculation" process run and how much load you have. The safe option is #3 but a lot more expensive in coding/testing. I also recommend always using .NET 4 for production systems using async design because there are some hard limits in .NET 3.5.