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Re: psycopg2 hang with multithread frequent queries

From: David Roid <dataroid(at)gmail(dot)com>
To: Federico Di Gregorio <fog(at)dndg(dot)it>
Cc: psycopg(at)postgresql(dot)org
Subject: Re: psycopg2 hang with multithread frequent queries
Date: 2012-09-14 17:15:39
Message-ID: CAKN1bq6EKO7cFKRMH_Sz3szeQbezsrr50gCV0kizWkiHwxiEzA@mail.gmail.com (view raw or flat)
Thread:
Lists: psycopg
Hi Federico,

No long-running trac, commit is done fair often. I also tried "one conn for
all threads" vs "one conn for one thread", and "one cursor all the way" vs
"use and throw away cursor", issue remains.

I install psycopg2.4.5 with easy_install, do I need to build psycopg2 from
source to enable debug info?

Thanks!
-David

2012/9/15 Federico Di Gregorio <fog(at)dndg(dot)it>

> On 14/09/2012 18:55, David Roid wrote:
> > And there are two kind of symptons after the process running for a
> > couple of minutes:
> > (0. At first it seems ok, each thread does its job, the quick one with
> > more logs of course)
> > 1. The quick one keeps running, the other two get no chance being called
> > any more
> > 2. When one of the slow ones get called, the whole python process hang,
> > with the postgresql process in 'idle in transaction'; note i'm very
> > alert with psycopg2's all-in-transaction style, i'm very sure there is a
> > commit/rollback to end the trac, the python process just stucks!
> >
> > I'm doing this test/investigate with freeload, so CPU/code conditions
> > should not be a cause, i'm starting to suspect psycopg2 or postgresql,
> > any hint?
>
> How many connections are you using? Cursors? Do you commit or keep a
> very long running transaction? Please give us some more information and
> compile psycopg with debugging enabled to have the logs ready for analsys.
>
> federico
>
> --
> Federico Di Gregorio                         federico(dot)digregorio(at)dndg(dot)it
> Studio Associato Di Nunzio e Di Gregorio                  http://dndg.it
>  There's no greys, only white that's got grubby. I'm surprised you
>   don't know that. And sin, young man, is when you treat people as
>   things. Including yourself.                       -- Granny Weatherwax
>

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