On Jul 11, 2008, at 9:23 AM, Ryan Parrish wrote:
> > Using SQLAlchemy 0.4.4 > > I am having a problem with SQLAlchemy where after the application that > uses SQLAlchemy has been sitting overnight and a user makes the first > queries of the day thru the app that uses SA, SQLAlchemy throws an > error saying 'MySQL server has gone away', which I understand the > reason to be that my mysql server has cut the idle connections, but I > have pool_recycle = 3600 set and I thought that was the solution to > keeping connections alive? > > After that error message I get two more exceptions when the user tries > the request again of "Can't reconnect until invalid transaction is > rolled back", which I don't understand at all because the application > only queries the DB and never deals with transactions. After those > three attempts, the forth request will go through just fine. :-\ Any > pointers on what I should look for or do? this indicates your application has checked out a Connection from the pool and is keeping it open, in a transaction. the connection then times out, and upon reaccess the next day would like to reconnect itself on next access; for a current Connection, this can reconnect its internal DBAPI connection transparently and you get to use the same Connection object. But Connection won't allow you to do this if its in a transaction, i.e. begin(); when the disconnect exception is thrown, it expects that to be within a try/except block which will do a rollback on error. The reason you're getting the disconnect exception in the first place is because the pool_recycle feature only works upon checkout from the pool. So the solution is the same, ensure all connections are returned to the pool after operations are complete. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~----------~----~----~----~------~----~------~--~---
