[pgpool-general: 3018] Re: pgpool watchdog pipe open error

Yugo Nagata nagata at sraoss.co.jp
Fri Jul 11 15:26:25 JST 2014

Hi Ryan,

On Wed, 09 Jul 2014 15:08:12 -0400
Ryan DeShone <rdeshone at liquidweb.com> wrote:

> Hash: SHA1
> Hello all,
> I'm experiencing an issue with pgpool 3.3.3 running on CentOS 6. If I
> enable the connection watchdog and configured the upstream trusted
> servers, when pgpool is started it will function fine for a while.
> After some time, however, it logs the following error repeatedly:
> pgpool[11188]: exec_ping: pipe open error:Too many open files
> Eventually, the wd_lifecheck will fail and watchdog will change status
> to DOWN even though the server is not, in fact, down.
> Jul  1 04:43:47 provdb-a pgpool[11188]: wd_lifecheck: failed to
> connect to any trusted servers
> Jul  1 04:43:47 provdb-a pgpool[11188]: gethostbyname() failed:
> Unknown host host: hostname
> Jul  1 04:43:47 provdb-a pgpool[11188]: send_packet_4_nodes: packet
> for hostname:9000 is canceled
> Jul  1 04:43:57 provdb-a pgpool[11188]: wd_lifecheck: watchdog status
> is DOWN. You need to restart pgpool
> While investigating this, I found that the number of open files for
> pgpool steadily increases as time goes on. It appears as if pgpool
> watchdog may not be closing its pipes properly. Has anyone else

Thanks for your reporting. Yes, that's right. pgpool doesn't close
pipes when ping command fails. This ping failure occurs when watchdog
confirms that specified IP is unused.

I attached a patch. Could your please try this.

> experienced this issue? Does anyone have a workaround for it? I'd
> really like to be able to turn the watchdog on to hopefully avoid an
> (admittedly, extremely unlikely in our setup) edge case which could
> result in split-brain, but it relies on having watchdog working with
> trusted IPs.
> - -- 
> Ryan DeShone
> Version: GnuPG v2
> Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/
> cpjdGLfEKmgxpL6/92Uw6ZxLllu8ht9sdMzk5jsKM1klsfgCDsj82g6cxVAOFMbl
> 8YE2D7Go9ZwvQQk8ggwt9bFxssFtUZI+69JtBKoFr1Ji3EpOPTblE63oOAbnnvVK
> Cr2DAKJXF7lV1Invu5g8fLQiJPOrF7OCEahSKEOB2g/lj8qTV9ETvRbr6JgexN3d
> yz7leCm4RQHX3plKF3PtL2v0qH3ysv3S8e5dYfkdixev5G5FiJYf4To2Re3ueEws
> DiQcOa91Ky09cvtRR5IpdKpUPRf/kR26eTxiK2LB/elKAGx21G3igIQG3S67zJw=
> =x8NZ
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Yugo Nagata <nagata at sraoss.co.jp>
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