Why on earth does a single error message correspond with multiple, completely unrelated conditions? Why can't there be a one to one mapping between error message and error condition?
I am so frustrated with "mysql server has gone away" I am very close to switching to Postgres. We might be forced to put aside 2 weeks learning a new database just because of some avoidable stupidity on the part of mysql.
"Why on earth does a single error message correspond with multiple, completely unrelated conditions?"
This aspect I am OK with. It is a client side error, raised when there is no connection to server. It is impossible to provide more details in the error message.
The problem is that you cannot get any more info from the server logs, even with the most detailed debug settings.
We might be forced to put aside 2 weeks learning a new database
More like 2 days, likely less. Unless you're using MySQL specific functionality (fulltext index?) or rely on MySQL specific bugs there shouldn't be much of a transition to speak of.
(I'm ofcourse assuming you have at most one MySQL host in production and not terabytes of data to re-import...)
An informative entry in MySQL log ("session dropped because of interactive_timeout") would also be nice, but let's not get over ourselves.