[pgpool-general: 1211] Re: Semphore errors after adding/removing hosts?

[Nick Webb]

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?


Nick

>
> 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