[ZODB-Dev] RelStorage and MySQL wait-timeout

[Shane Hathaway]

On 02/01/2011 10:01 AM, Chris Withers wrote:
> OperationalError: (2006, 'MySQL server has gone away')
>
> ...which feels a little on the serious side for (what is for MySQL)
> quite a normal situation to be in.

Random disconnects are unacceptable for RelStorage.  If MySQL goes away 
outside transaction boundaries, we *have* to propagate the exception to 
the application; otherwise consistency is lost.  We can only reconnect 
at the next request or transaction boundary.

> (Mike Bayer could probably shed some light given the connection pool
> stuff that SQLAlchemy does to deal with MySQL's behaviour...)

Unfortunately, the generic behavior implemented by SQLAlchemy would not 
work here.  It would scramble ZODB.

Shane