Django + FastCGI - randomly raising OperationalError

Question

I\'m running a Django application. Had it under Apache + mod_python before, and it was all OK. Switched to Lighttpd + FastCGI. Now I randomly get the following exception (ne

Answer 1

I try to give an answer to this even if I'am not using django but pyramid as the framework. I was running into this problem since a long time. Problem was, that it was really difficult to produce this error for tests... Anyway. Finally I solved it by digging through the whole stuff of sessions, scoped sessions, instances of sessions, engines and connections etc. I found this:

http://docs.sqlalchemy.org/en/rel_0_7/core/pooling.html#disconnect-handling-pessimistic

This approach simply adds a listener to the connection pool of the engine. In the listener a static select is queried to the database. If it fails the pool try to establish a new connection to the database before it fails at all. Important: This happens before any other stuff is thrown to the database. So it is possible to pre check connection what prevents the rest of your code from failing.

This is not a clean solution since it don't solve the error itself but it works like a charm. Hope this helps someone.