"MySQL server has gone away" error after long idle

Question

I know this issue is not a new one on SO but I'm unable to find a solution. Whenever I return to my desk after leaving my app running overnight, I get a MySQL server has gone away error that persists until I restart my uwsgi service. I've already done the following:

• pool_recycle=some really large number in my create_engine() call
• Added a ping_connection() after a @event.listens_for() decorator (and I can't use pool_pre_ping - that breaks my create_engine() call)
• in /etc/my.cnf I added wait_timeout and interactive_timeout params with large values

but nothing has had any effect.

Answer 1

From the sqlalchemy doc located here, the pool_recycle feature is what you are looking for.

from sqlalchemy import create_engine

engine = create_engine("mysql://scott:tiger@localhost/test", pool_recycle=28700)

Set pool_recycle to a value < wait_timeout in your mysql configuration file my.cnf

MySQL default wait_time is 28800 (8 hrs)

Dont forget to restart your services (i.e. mysql, etc) if you do modify the conf files