[pgpool-general: 5583] Re: How to find what caused queries to get stuck

[Tatsuo Ishii]

> Hi experts,
> 
> 1) I tried to find a scenario that caused queries to get stuck on my system.  But since it does not happen very often it is hard to find such scenario.  However, when I tried to open all possible logging options as it was suggested, I got several GB of log data per hour and I needed to stop it.  Please send me which logging options should be enabled so I can still get all the information needed for debugging and at the same time have manageable log file size.

You can use logroate or something like that to limit the total amount
of log volume.  What we need is the last (say) 1GB of logs when the
hang happens.

> 2) I saw that the next pgpool version has a fix for a hanging queries problem.  How can I check to see if my system also has this problem that is fixed in the next version.
> Take.

Grab the latest source code from the git repository, compile, install
it. For 3.6 stable tree, visit:
https://git.postgresql.org/gitweb/?p=pgpool2.git;a=shortlog;h=refs/heads/V3_6_STABLE

> 3) When is the next minor version expected to be released.

Not decided yet but we think about July.

Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp

> Thanks
> Avi
> -----Original Message-----
> From: Tatsuo Ishii [mailto:ishii at sraoss.co.jp]
> Sent: Wednesday, June 07, 2017 6:03 AM
> To: Avi Weinberg <AviW at gilat.com>
> Cc: pgpool-general at pgpool.net
> Subject: Re: [pgpool-general: 5558] How to find what caused queries to get stuck
> 
> Without fully understanding Pgpool-II source code, it would be pretty hard to find the cause of stuck. Instead, I recommend you help developers to provide enough information so that they can tackle on it. i.e.
> 
> - Pgpool-II version
> - pgpool.conf
> - Pgpool-II debug log
> - Self contained test case
> 
> Especially the last one is very important.
> 
> Best regards,
> --
> Tatsuo Ishii
> SRA OSS, Inc. Japan
> English: http://www.sraoss.co.jp/index_en.php
> Japanese:http://www.sraoss.co.jp
> 
>> Hi all,
>>
>> We are using postgres 9.6 and 9.7 with pgpool 3.6.3.
>>
>> On setups using pgpool every so often we see "stuck" queries that are shown as idle in transaction.  Other setups that skip pgpool and connect directly to postgres never get those idle in transaction queries.
>> We got to a point where we are forced to monitor our database and kill queries that are idle for more than x minutes, but obviously  we cannot keep it this way.
>>
>> How can I find what cause those queries to get stuck?
>>
>> Thanks
>> Avi
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