[pgpool-general: 2879] Re: Problems with the LOCK patch in Bind phase included in 3.3.2

[Yugo Nagata]

Hi,


On Mon, 19 May 2014 12:20:35 +0200
Jose Maria Alvarez Fernandez <josemaria.alvarez at 2020mobile.es> wrote:

> Hi all,
> 
> I am writing because I would need some help with a strange behaviour we are
> having with our pgpool2 installation.
> 
> Our deployment includes two Postgresql 9.3.4 servers in synchronous
> streaming replication, and a pgpool2 cluster with watchdog configured to
> access them, in replication mode and with load balancing.
> 
> When we deployed the 3.3.2 versión, we saw an unexpected behaviour that
> wasn't there in the 3.3.1 release. Our application started to get deadlocks
> when introducing data from different threads simultaneously. I think I've
> narrowed the problem to this bugfix introduced in 3.3.2:
> 
> Fix data inconsistency problem with native replication mode + extended
>       protocol case
> 
> Per bug report by Steve Kuekes in [pgpool-general: 2142].
>       http://www.sraoss.jp/pipermail/pgpool-general/2013-September/002171.html

How did you check the commit is the problem? By usign git bisect?

For analysis, the exact log messages of pgpool with log_statement=on 
and backend log are helpful for me. Could you please send me this?

> 
> It seems that, as our application is using OpenJPA to manage data, and
> it doesn't ensure the insert order, some of the inserts trying to get
> a lock in a table that other thread as already locked, but this thread
> is also trying to acquire a lock in a table that the other thread has
> already locked, due to the unordered insert statements.
> 
> Does anyone have an idea of how can we workaround this, to keep pgpool2
> versions up to date? I haven't found an option to force OpenJPA to "order"
> the inserts.
> 
> Thank you all,
> 
> Jose Maria.
> 
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> 
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-- 
Yugo Nagata <nagata at sraoss.co.jp>