[pgpool-general: 1212] Re: Semphore errors after adding/removing hosts?

[Tatsuo Ishii]

> On Fri, Nov 30, 2012 at 6:25 PM, Tatsuo Ishii <ishii at postgresql.org> wrote:
>> We have fixed pcp_attach_node/detach_node prblem recently.
>> Can you try git snapshot?
> 
> Thanks Tatsuo.  I'm actually using 3.1.5, do you think upgrading to
> 3.2.x snapshot may still help?

You can use 3.1-stable snapshot. The fix is in the tree as well.

http://git.postgresql.org/gitweb/?p=pgpool2.git;a=shortlog;h=refs/heads/V3_1_STABLE
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp

>> If yuo are using 3.2.x, this is for you:
>> http://git.postgresql.org/gitweb/?p=pgpool2.git;a=shortlog;h=refs/heads/V3_2_STABLE
>> --
>> Tatsuo Ishii
>> SRA OSS, Inc. Japan
>> English: http://www.sraoss.co.jp/index_en.php
>> Japanese: http://www.sraoss.co.jp
>>
>>> Hello,
>>>
>>> I'm fairly new to pgpool, but am already quite a fan, thanks for the great
>>> software!
>>>
>>> When using the pcp_detach_node command followed by pcp_attach_node after
>>> doing some maintenance on a backend, I start getting errors like this in
>>> the log:
>>>
>>> Nov 27 03:09:02 PGLB pgpool-X[32282]: semop(id=884737) failed: Invalid
>>> argument
>>> Nov 27 03:09:02 PGLB pgpool-X[10230]: semop(id=884737) failed: Invalid
>>> argument
>>> Nov 27 03:09:02 PGLB pgpool-X[10230]: semop(id=884737) failed: Invalid
>>> argument
>>>
>>> These continue over and over until the process is restarted.
>>>
>>> I ignored them when I first saw it, as it seemed to function just fine, but
>>> a few days later our application could not connect to PGPool very well, it
>>> was very slow and most connections timed out despite the system load and
>>> CPU being very low.  Connections from the PGPool host to
>>> the back-ends directly were also very quick (via psql command).
>>>
>>> Stopping and starting PGPool immediately returned the service to normal
>>> performance levels.
>>>
>>> Are these two issues linked?  How can I stop from getting the semop error
>>> when attaching hosts?
>>>
>>> It also seems that about every 3rd or 4th pcp_ command I run hangs,
>>> seemingly waiting until open connections finish... and I think it finish
>>> after a few minutes.  This may be related, as I seem to recall one of these
>>> "hangs" when adding the backend back to the pool, then seeing the semop
>>> errors (could have been the detach that hung, not sure).
>>>
>>> Thanks!
>>>
>>> Nick