[wisty]

IIRC, another thing which keeps processes open is database access.

I'm not sure, but I think that with Apache + Django, you get something like: Apache gets request, gives it to Django, Django asks MySQL for a value, waits, waits, waits (taking up lots of memory, but not too much CPU, but your host charges for RAM), waits a little more, gets a value from MySQL, puts it in a template, hands the response to Apache, which then sends the response to the client.