ASP.NET MVC and Ajax, concurrent requests?

Question

AJAX newbie here!
At the moment in my ASP.NET MVC web app my AJAX requests appear to be getting batched or queued, im not sure.
No requests seem to be getting completed until the previous request has finished.
How do I go about getting the requests to return independantly?
I dont necessarily want someone to give me the answer but maybe some links to good tutorials or resources which could help. Thanks

Answer 1

I'm expanding on Lachlan Roche's answer, which is correct.

The ASP.NET framework will "single-thread" requests that deal with Session scope (a global resource), to prevent one request from interfering with another. In WebForms I think you can use the Page directive to specify that individual pages don't use Session and therefore don't need to treated synchronously like this.

The problem is that in ASP.NET MVC all requests use Session, because it's used to implement TempData. You can disable session state entirely, as Lachlan Roche pointed out, or you can deal with this on a case-by-case basis.

A possible solution might be to kick off your own background threads to process any long-running code, so that the initial request "completes" as quickly as possible.