Diagrams/Explanations of Django request processing?

There is this diagram from The Django Book (online version):

A breakdown of this process is described in Chapter 3 under the heading How Django Processes a Request: Complete Details.

I think this article includes the information you're looking for with a decent (if cluttered) diagram: http://uswaretech.com/blog/2009/06/django-request-response-processing/

You can also use the django-debug-toolbar to get more info about the SQL (and lots of other stuff) happening on behind the scenes of a particular request.