Multiple request in the same controller causing problems with SQLAlchemy Session object

[Alan Castro]

Hello,

Latelly I've been running into this issue:

OperationalError: (OperationalError) (2013, 'Lost connection to MySQL
server during query') SELECT...

To contextualize, I developed a Pylons application using
scoped_session (default in pylons). And it was working until I created
some extra processes of my application.

Thanks

Alan

[Michael Bayer]

DBAPI connections don't travel well over process boundaries. You need to call create_engine() inside each new child process.

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[Warwick Prince]

Hi Alan

We're also doing battle with this one.. One thing I did find was if I had large(ish) BLOB values, MySQL would go away. I found that I had to tweak some settings on MySQL to allow for larger sizes. (The default settings appear to be ridiculously small). Let me know what else you find, as it is a very annoying issue for us as well. BTW: What connector are you using?

Cheers
Warwick

Warwick Prince
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[Alan Castro]

Hi guys,

An update: Mike is right! The connector doesn't get along with child
processes... For a quick setup and since I'm using uWSGI and Nginx, I
just created a cluster o uwsgi connections and ran 3 independent
process of my application. All my tests passed nicely.

@Warwick I'm using mysql-python (MySQLdb). And try to follow what Mike
said and test it and see if you still get the errors.

Tomorrow I'll run more tests at work but I think it is solved.

Thanks Mike!

Regards

Alan