I ran into a mysterious, transient exception this week using django-celery.
DatabaseError: server closed the connection unexpectedly This probably means the server terminated abnormally before or while processing the request.
At other times, I was seeing a slightly different error message.
InterfaceError: connection already closed
After some searching, I found resolved issue #149 in the django-celery maintainer's github issues's list. It turns out that it's specifically a postgres issue, and only happens when the number of workers (the "c" parameter) is greater than one. Note: it defaults to the number of cores on your system.
A new issue #46 has been opened, so this will likely get fixed. In the meantime, you can monkey patch the code to fix it yourself.
sudo vim /usr/local/lib/python2.6/dist-packages/djcelery/loaders.py # inside DjangoLoader def on_task_init(self, task_id, task): self.close_database()