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I have a custom Django app that's becoming unresponsive roughly every 5,000 requests. In the apache logs, I see see the following:

Apr 13 11:45:07 www3 apache2[27590]: **successful view render here**
Apr 13 11:47:11 www3 apache2[24032]: [error] server is within MinSpareThreads of MaxClients, consider raising the MaxClients setting
Apr 13 11:47:43 www3 apache2[24032]: [error] server reached MaxClients setting, consider raising the MaxClients setting
Apr 13 11:50:34 www3 apache2[27617]: [error] [client] Script timed out before returning headers: django.wsgi
(repeated 100 times, exactly)

I believe I am running WSGI 2.6 (/usr/lib/apache2/modules/mod_wsgi.so-2.6) with the following config:

apache config

WSGIDaemonProcess site-1 user=django group=django threads=50
WSGIProcessGroup site-1
WSGIScriptAlias / /somepath/django.wsgi


import os, sys
os.environ['DJANGO_SETTINGS_MODULE'] = 'myapp.settings'    
import django.core.handlers.wsgi    
application = django.core.handlers.wsgi.WSGIHandler()

When this happens, I can kill the wsgi process and the server will recover.

>ps aux|grep django # process is running as user "django"
django   27590  5.3 17.4 908024 178760 ?       Sl   Apr12  76:09 /usr/sbin/apache2 -k start
>kill -9 27590

This leads me to believe that the problem is a known issue:

deadlock-timeout=sss (2.0+)

Defines the maximum number of seconds allowed to pass before the daemon process is shutdown and restarted after a potential deadlock on the Python GIL has been detected. The default is 300 seconds. This option exists to combat the problem of a daemon process freezing as the result of a rouge Python C extension module which doesn't properly release the Python GIL when entering into a blocking or long running operation.

However, I'm not sure why this condition is not clearing automatically. I do see that the script timeout occurs exactly 5 minutes after the last successful page render, so the deadlock-timeout is getting triggered. But it does not actually kill the process.

Edit: more info

  • apache version 2.2, using the worker MPM
  • wsgi version 2.8
  • SELinux NOT installed l
  • xml package being used, infrequently
  • Ubuntu 10.04
share|improve this question
FYI - Some more info here groups.google.com/group/modwsgi/browse_thread/thread/… –  Chase Seibert Apr 15 '11 at 17:35
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