Apache stops processing requests (mod_wsgi?)

Question

At some point my site, running on Apache2 with mod_wsgi just stops processing requests. The connection to server is maintained and client waits for responce, b

Answer 1

Sounds like you are using embedded mode to run the multiple applications and you are using third party C extensions that have problems in sub interpreters, resulting in potential deadlock. Else your code is internally deadlocking or blocking on external services and never returning, causing exhaustion of available processes/threads.

For a start, you should look at using daemon mode and delegate each web application to a distinct daemon process group and then forcing each to run in the main interpreter.

See:

http://code.google.com/p/modwsgi/wiki/QuickConfigurationGuide#Delegation_To_Daemon_Process http://code.google.com/p/modwsgi/wiki/ApplicationIssues#Python_Simplified_GIL_State_API

Otherwise use debugging tips described in:

http://code.google.com/p/modwsgi/wiki/DebuggingTechniques

for getting stack traces about what application is doing.