From: Manoj Govindassamy <manoj@nimblestorage.com>
To: Fujii Masao <masao.fujii@gmail.com>
Cc: pgsql-general@postgresql.org
Cc: pgsql-admin@postgresql.org
Subject: Re: PG synchronous replication and unresponsive slave
Date: Tue, 17 Jan 2012 17:54:04 -0800
Message-ID: <4F16263C.2050309@nimblestorage.com> (raw)
In-Reply-To: <CAHGQGwFNLAQOT7Rfz2z=bSjgf4S5hFj0xx7F1jP0XnCjVmM3GQ@mail.gmail.com>
References: <4F0E0438.5070300@nimblestorage.com>
<4F0F229F.30308@nimblestorage.com>
<4F1471AB.9060008@nimblestorage.com>
<CAHGQGwH5R-iinVkQgmsnUOJJpczY6c-xkwBtcs+wfw9MjzVCNQ@mail.gmail.com>
<4F15EA2F.2040703@nimblestorage.com>
<CAHGQGwFNLAQOT7Rfz2z=bSjgf4S5hFj0xx7F1jP0XnCjVmM3GQ@mail.gmail.com>
I am aware of pgpool-II and its features. Just that my requirements are
little different. I have a System (PG runs on it) which already has
Failover mechanism to another System and I want PG to be part of this
cluster and not clustered on its own. Mean, PG has to be running in
Master system and in synchronous replication mode with another slave
system, but the failover is driven from the higher level and not just on
PG's failure.
So, whenever PG's slave node is unresponsive, we better let the
replication cutoff and run the master system independently. So, we need
better mechanism to detect when Master PG's synchronous replication not
working as expected or when the slave PG is going unresponsive. If not,
master PG is held back by the slave PG and so the whole clustered system
is stuck. Hope, I am making some sense here. Let me know if there are
easy ways to detect Master PG's replication not working (via libpq would
be more preferable).
thanks,
Manoj
On 01/17/2012 05:04 PM, Fujii Masao wrote:
> On Wed, Jan 18, 2012 at 6:37 AM, Manoj Govindassamy
> <manoj@nimblestorage.com> wrote:
>> (2) We are not comfortable moving to PGPool just for automatic failback mode
>> on hot-standby failure.
> Hmm.. my reply might be misleading. What I meant was to use pgpool-II
> as a clusterware for PostgreSQL built-in replication, not as a replication
> itself. You can health-check, do failover if necessary and manage the
> PostgreSQL replication by using pgpool-II. AFAIK pgpool-II has such an
> operation mode. But you are still not comfortable in using pgpool-II in
> that way?
>
> Regards,
>
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-admin@postgresql.org
Cc: manoj@nimblestorage.com, masao.fujii@gmail.com, pgsql-general@postgresql.org
Subject: Re: PG synchronous replication and unresponsive slave
In-Reply-To: <4F16263C.2050309@nimblestorage.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox