Mysterious Apache Django WSGI Error

I'm running a django application on apache with mod_wsgi. The apache error log is clean except for one mysterious error.

Exception exceptions.TypeError: "'NoneType' object is not callable" in <bound method SharedSocket.__del__ of <httplib.SharedSocket instance at 0x82fb138c>> ignored

I understand that this means that some code is trying to call SharedSocket.del, but it is None. I have no idea what the reason for that is, or how to go about fixing it. Also, this error is marked as ignored. It also doesn't seem to be causing any actual problems other than filling the log file with error messages. Should I even bother trying to fix开发者_Python百科 it?

It is likely that this is coming about because while handling an exception a further exception is occurring within the destructor of an object being destroyed and that the latter exception is unable to be raised because of the state of the pending one. Within Python C API details of such can be written direct to error log by PyErr_WriteUnraisable().

So, it isn't that the del method is None, but some variable it is trying to use from code executed within the del method is None. You would need to look at the code for SharedSocket.del to work out exactly what is going on.

Note: this is more of a pointer than an answer, but I couldn't get this to work in a comment.

I did some googling on the error message and there seems to be a group of related problems that crop up in Apache + mod_wsgi + MySQL environments. The culprit may be that you are running out of simultaneous connections to MySQL because of process pooling, with each process maintaining an open connection to the DB server. There are also indications that some non-thread-safe code may be used in a multi-thread environment. Good luck.