[uWSGI] Problem with multiple processes with httplib.HTTPConnection?

Alan Castro alanclic at gmail.com
Tue Nov 9 22:09:12 CET 2010


Roberto,

I've created a very simple pylons application as fast as possible that
reproduces the error with mysql adapter.

You can clone it at:
git clone git://github.com/alancastro/simpleapp.git

There is a simple readme there too: http://github.com/alancastro/simpleapp

Thank you

Alan

On Tue, Nov 9, 2010 at 4:52 PM, Alan Castro <alanclic at gmail.com> wrote:

> The -i didn't solve it..
>
> I'll work on a simple app and reproduce the problem from there and I'll
> send it to you.
>
> Thanks alot for the attention
>
> Alan
>
>
> On Tue, Nov 9, 2010 at 4:35 PM, Roberto De Ioris <roberto at unbit.it> wrote:
>
>>
>> > Hi Roberto,
>> >
>> > I tried uwsgi last last version with --threads and the current stable
>> with
>> > -T and the problem still occurs..
>> >
>> > The real problem is SQLAlchemy + Pylons + Multi-process.
>> >
>> > Summaryzing:
>> >
>> > There are 2 situations where everything works:
>> >
>> > * when I comment out the every db related code and deploy on a
>> > 'multi-process environment'.
>> >
>> > * and if I use a '1 process environment' with db related code.
>> >
>> > And 1 situation (the one I really wanted to work) that does not work:
>> >
>> > * 'multi-process environment' with db related code.
>>
>>
>> Can you change the db adapter (something like postgres or sqlite) to see
>> if the problem is oracle related ?
>>
>> Another problem can be (i have never used the oracle adaptor) with
>> multiple interpreters, try passing the -i option to a stable release.
>>
>> If both still do not works, can you send a skeletal app that i can use for
>> tests ?
>>
>> Thanks a lot
>>
>>
>> >
>> > Thanks
>> >
>> > Alan
>> >
>> > On Tue, Nov 9, 2010 at 3:55 PM, Roberto De Ioris <roberto at unbit.it>
>> wrote:
>> >
>> >>
>> >> > I just deployed with the current version of mercurial and when i use
>> >> -T
>> >> > option my app won't work. (without -T it works)
>> >> >
>> >> > The "ready_to_reload..." is a normal debug info?
>> >>
>> >>
>> >>
>> >> Please try the -T with the current stable releases, and --threads <n>
>> >> (use a low number like 4) with the mercurial one
>> >>
>> >> >
>> >> > Thanks
>> >> >
>> >> > Alan
>> >> >
>> >> > On Tue, Nov 9, 2010 at 3:05 PM, Roberto De Ioris <roberto at unbit.it>
>> >> wrote:
>> >> >
>> >> >>
>> >> >> Il giorno 09/nov/2010, alle ore 17.39, Alan Castro ha scritto:
>> >> >>
>> >> >> > Roberto,
>> >> >> >
>> >> >> > I'm still facing this problem.
>> >> >> >
>> >> >> > Let me context my problem: I developed a Pylons application (which
>> >> is
>> >> >> multithreaded, each request fires up a new thread) and is working
>> >> fine
>> >> >> (deployed with uwsgi with one process). When I run it on a
>> >> multiprocess
>> >> >> with
>> >> >> uwsgi eveything goes out of control and I keep getting this Oracle
>> >> error
>> >> >> TNS: Bad packet, which looks like problem with my sqlalchemy session
>> >> >> object.
>> >> >> >
>> >> >> > I know this runs a bit out of uwsgi context, but do you know how
>> >> much
>> >> >> uwsgi multiprocess environment affects pylons multithreaded? In my
>> >> head
>> >> >> everything should work fine.
>> >> >> >
>> >> >>
>> >> >> I suppose that your app generate a new python thread at every
>> request
>> >> >> that
>> >> >> do something in the background and pass data to the "main" thread
>> >> that
>> >> >> will
>> >> >> send the response to the webserver; in this case, have you enabled
>> >> the
>> >> >> -T
>> >> >> option ?
>> >> >> Without it the GIL is not initialized and i do not know what could
>> >> >> happen
>> >> >> :)  If instead your app generate a new thread that "alone" manages
>> >> the
>> >> >> whole
>> >> >> request
>> >> >> (so the thread itself generate the wsgi response) this will cause
>> all
>> >> >> sort
>> >> >> of problems, as the current uWSGI stable releases are not
>> >> multithreaded
>> >> >> (you
>> >> >> have to use
>> >> >> a 0.9.7-dev release from mercurial repository)
>> >> >>
>> >> >> --
>> >> >> Roberto De Ioris
>> >> >> http://unbit.it
>> >> >>
>> >> >> _______________________________________________
>> >> >> uWSGI mailing list
>> >> >> uWSGI at lists.unbit.it
>> >> >> http://lists.unbit.it/cgi-bin/mailman/listinfo/uwsgi
>> >> >>
>> >> > _______________________________________________
>> >> > uWSGI mailing list
>> >> > uWSGI at lists.unbit.it
>> >> > http://lists.unbit.it/cgi-bin/mailman/listinfo/uwsgi
>> >> >
>> >>
>> >>
>> >> --
>> >> Roberto De Ioris
>> >> http://unbit.it
>> >> _______________________________________________
>> >> uWSGI mailing list
>> >> uWSGI at lists.unbit.it
>> >> http://lists.unbit.it/cgi-bin/mailman/listinfo/uwsgi
>> >>
>> > _______________________________________________
>> > uWSGI mailing list
>> > uWSGI at lists.unbit.it
>> > http://lists.unbit.it/cgi-bin/mailman/listinfo/uwsgi
>> >
>>
>>
>> --
>> Roberto De Ioris
>> http://unbit.it
>> _______________________________________________
>> uWSGI mailing list
>> uWSGI at lists.unbit.it
>> http://lists.unbit.it/cgi-bin/mailman/listinfo/uwsgi
>>
>
>
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