This post is a reminder to myself and maybe other that will stumble upon "Mysql server has gone away" error with SQLAlchemy.
Recently, we had problem again with MySQL and SQLAlchemy application, that it lost connection, resulting in this error. While a colleague of mine started panicking, I've started to remind myself, how did we solved it last time.
Well.. the answer is simple, we used pool_recycle because mysql closes itself stale connections.
I don't think this problem occurs with postgresql, at least I haven't seen it anywhere with postgresql, but for MySQL it's certainly worth trying first pool_recycle option, and tuning pooling in general, before franticly browsing internet for possible cause of this broad error.