What are some scenario's of having a Session-less Controller in ASP.NET MVC3?

Question

Reading Guru-Gu\'s blog post about ASP.NET MVC3 hitting RC, he says:-

Session-less Controller Support

You can now indicate whether you wan

Answer 1

Gu commented about this. Quoting:

The release notes cover this more (you can download them from the download link above). Session state is designed so that only one request from a particular user/session occurs at a time. So if you have a page that has multiple AJAX callbacks happening at once they will be processed in serial fashion on the server. Going session-less means that they would execute in parallel.

This is a known scenario in ASP.NET in general. The session object for the same user is not thread safe. This means that if the same user (same session id cookie) sends multiple requests to a page which uses session those requests will queue and will be processed in series and not in parallel.