I still seem to get the 'MySQL server has gone away' Error.
I am suspecting that the problem is in my use of FCGI in production.
Thats the only difference between my Development environment and
Production and it works 100% without the error in Development env.
I guess I'll have to put some more debugging in my application in
Production setup.
Oh and, after the 'MySQL server has gone away' Error, I immediately
get the "InvalidRequestError: Can't reconnect until invalid
transaction is rolled back".
SQLAlchemy version I'm running by the way is '0.4.6'.
I created a WSGI middleware class that handles the SQLAlchemy
Connections and Sessions like so:
Note: the middleware instance gets loaded only once on start of the
application. And the get_engine() method lazy-loads the engine once
and then returns existing thereafter.
sql.py
====================================
class SQLAlchemyMiddleware(object):
"""
Middleware for providing clean SQLAlchemy Session objects for each
Request.
"""
def __init__(self, application):
self.application = application
self.__engine = None
def get_engine(self):
if self.__engine is None:
self.__engine = create_engine(
settings.SQLALCHEMY_DEFAULT_URL,
pool_recycle=3600,
pool_size=20,
echo_pool=True
)
return self.__engine
def init_model(self, engine):
"""Call before using any of the tables or classes in the
model."""
sm = orm.sessionmaker(autoflush=True, transactional=True,
bind=engine)
meta.engine = engine
meta.Session = orm.scoped_session(sm)
def __call__(self, environ, start_response):
try:
engine = self.get_engine()
self.init_model(engine)
return self.application(environ, start_response)
finally:
if meta.Session is not None:
meta.Session.remove()
====================================
models/meta.py
====================================
from sqlalchemy import MetaData
__all__ = ['engine', 'metadata', 'Session']
engine = None# Global metadata. If you have multiple databases with
overlapping table
# names, you'll need a metadata for each database.
Session = None
metadata = MetaData()
====================================
Regards,
-Alen
On Aug 15, 4:44 pm, Alen Ribic <[EMAIL PROTECTED]> wrote:
> > one-per-application level
>
> That seems to have worked. I'll monitor the log for the next day or so
> and see how it goes.
>
> Thx
>
> -Alen
>
> On Aug 15, 4:27 pm, Michael Bayer <[EMAIL PROTECTED]> wrote:
>
> > On Aug 15, 2008, at 10:21 AM, Alen Ribic wrote:
>
> > > To me it seems like the connections are not being returned back to the
> > > pool.
> > > Here is my engine code which gets called on each user HTTP request:
>
> > > engine = create_engine(
> > > settings.SQLALCHEMY_URL,
> > > pool_recycle=3600,
> > > pool_size=20,
> > > echo_pool=True
> > > )
>
> > if you call create_engine() on every request, then you're creating a
> > new connection pool for every request. move this up to the module one-
> > per-application level.
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