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 want a
Controller class to use session-state
– and if so whether you want it to be
read/write or readonly.read/write or readonly.

Can someone explain what are some scenario’s someone might want to have a session-less controller? or a read-only controller?

I’ve always been creating a separate IIS website which I use to handle all static images/content and then have this same website have session state turned off … so no cookies are sent over the wire. Is this a similar scenario?

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.