Pita/etherpad-lite — pull request #341 by azul (2012-01-19 16:43:07+00:00)
Title: make PadMessageHandler more robust against timing issues

I'm using etherpad on top of a remote connection so database access is way slower than usual - also i was not using caching at that time.
What I observed was the server crashing during text updates because the sessioninfos[session] was null.
It had been deleted by another user who left in the meantime. I guess this is really rare with other databases - in particular with caching but I think it's a race condition never the less.