Truncated or oversized response headers received from daemon process
I recently migrated a python django application from a debian system to a redhat enterprise distribution. The application is hosted using httpd, mod_wsgi and running in a venv in an daemon process. On large requests I now get following error message in the log file:
"Truncated or oversized response headers received from daemon process"
I have never experienced anything like this and Google is not the key here as well. I checked configuration of apache, but no config is related to response headers in there.
My httpd.conf configuration looks like this ( pretty standard):
WSGIPassAuthorization On
WSGIScriptAlias / /var/www/myapp/wsgi.py
WSGIDaemonProcess my.name python-path=/path/to/myapp/:/path/to/venv/lib/python2.7/site-packages display-name=%{GROUP}
WSGIProcessGroup my.name
Does any Guru have a hint in which direction I should look?
Answer
We recently ran into this issue, and after days of vigorous ugoogleizing and massive headache, we discovered that we were using psycopg2-binary as our database connector dependency (I know, newbs)! It states right in their documentation not to use the package in a production environment.
We did add all the other proposed answers such as adding 'WSGIApplicationGroup %{GLOBAL}' to our settings (which we kept), but all of them alone and together didn't solve the issue.
We also found that other C libraries like numpy, cause issues.
Hope this helps someone some day.
Django Webfaction 'Timeout when reading response headers from daemon process'