[Pgpool-general] hanging pgpool processes during massive UPDATEs

[Yoshiyuki Asaba]

Hi,

From: "Felix J. Ogris" <fjo-lists at ogris.de>
Subject: [Pgpool-general] hanging pgpool processes during massive UPDATEs
Date: Wed, 10 Oct 2007 17:12:53 +0200

> we are experiencing some strange problems with pgpool-II-1.2.1 on CentOS 4.5
> running version 2.6.9 of the Linux kernel. During massive UPDATEs, which are
> interrupted by user interaction, some pgpool processes start consuming all
> CPU time. System load goes up to N, where N denotes the count of hanging
> pgpool processes. Strace shows no output if attached to one of these
> processes. `ps ax` still shows these pgpool processes with their client
> connection info and current action (UPDATE) as process title. But there
> aren't any active PostgreSQL processes on the backend servers. We don't see
> any errors in the debug log. So I assume that pgpool goes into some kind of
> an endless loop.

Could you show us pgpool.conf and backtrace?

  % gdb -p <PID> --batch --ex bt


> This one looks very strange as "statement2" is empty:

If you send "\n select 1" to pgpool, output following.

----
2007-10-11 11:18:28 DEBUG: pid 23489: statement2:
select 1
----

Could you show us a result of the following command?

  % grep 559 log | grep -A1 statement2

Regards,
--
Yoshiyuki Asaba
y-asaba at sraoss.co.jp