I have a variable in init of a module which get loaded from the database and takes about 15 seconds. 
For django development server everything is working fine but looks like with apache2 and mod_wsgi the module is loaded with every request (taking 15 seconds).
Any idea about this behavior? 
Update: I have enabled daemon mode in mod wsgi, looks like its not reloading the modules now! needs more testing and I will update.
I guess, you had a value of 1 for MaxClients / MaxRequestsPerChild and/or ThreadsPerChild in your Apache settings. So Apache had to startup Django for every mod_python call. That's why it took so long. If you have a wsgi-daemon, then a restart takes only place if you "touch" the wsgi script.
Python module being reloaded for each request with django and mod_wsgi