From: Guillaume Lelarge <guillaume@lelarge.info>
To: Michael Holt <michael@aers.ca>
Cc: pgsql-admin@postgresql.org
Subject: Re: Streaming replication status and fail over questions
Date: Sat, 04 Jun 2011 00:10:45 +0200
Message-ID: <1307139045.2026.6.camel@laptop> (raw)
In-Reply-To: <BANLkTi=GMRpVaFDAz_8Jj58bT4SnC72=WA@mail.gmail.com>
References: <BANLkTi=GMRpVaFDAz_8Jj58bT4SnC72=WA@mail.gmail.com>
On Fri, 2011-06-03 at 11:07 -0700, Michael Holt wrote:
> I'm investigating moving from slony to streaming replication as we
> plan some upgrades from 8.x versions of postgres to 9. I've managed to
> get it working but there's a couple questions I've been unable to find
> answers to so far.
>
> 1) I've seen things about using pg_current_xlog_location(),
> pg_last_xlog_replay_location(), pg_last_xlog_receive_location() to
> check replication status, but how can this tell me either the time lag
> or actual query lag?
It can't.
> Do I need to wait for 9.1 and it's replication monitoring features?
>
It will only give you time lag (and some nice views, but no query lag).
> 2) If I have a master to multi-slave setup and need to fail over, is
> there anyway for slaves to detect the new master?
Automatically, no.
> Without this it seems like fail over could be pretty messy.
>
Failover isn't messy. Switchover, in the other hand, is pretty
difficult.
> 3) Finally just wanted to confirm that SR allows only for replication
> of an entire server.
>
Yes.
--
Guillaume
http://blog.guillaume.lelarge.infohttp://www.dalibo.com
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To: pgsql-admin@postgresql.org
Cc: guillaume@lelarge.info, michael@aers.ca
Subject: Re: Streaming replication status and fail over questions
In-Reply-To: <1307139045.2026.6.camel@laptop>
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