Re: Clean shutdown and warm standby

From: Guillaume Smet <guillaume(dot)smet(at)gmail(dot)com>
To: Simon Riggs <simon(at)2ndquadrant(dot)com>
Cc: Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Andreas Pflug <pgadmin(at)pse-consulting(dot)de>, Fujii Masao <masao(dot)fujii(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Clean shutdown and warm standby
Date: 2009-05-28 15:50:10
Message-ID: 1d4e0c10905280850g70ccd69fv437211703f116ab5@mail.gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

On Thu, May 28, 2009 at 5:36 PM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> If you feel we have moved forwards, that's good, but since no part of
> the *safe* maintenance procedure has changed, I don't see that myself.
> Only the unsafe way of doing it got faster.

I disagree with you.

The situation was:
- you stop the master;
- everything seems to be OK in the log files (archiving and so on);
- it's broken anyway as you don't have the last log file;
- you have to copy the last log file manually.
- you can start the slave.

It is now:
- you stop the master;
- if everything is OK in the log files, the last log file has been
archived (and yes I check it manually too) and it's done. If not (and
it's the exception, not the rule) I have to copy manually the missing
WAL files;
- you can start the slave.

I think it's a step forward, maybe not sufficient for you but I prefer
the situation now than before. It's safer because of the principle of
least surprise: I'm pretty sure a lot of people didn't even think that
the last WAL file was systematically missing.

As Heikki stated it, if you have concrete proposals of how we can fix
the other corner cases, we're all ears. Considering my current level
of knowledge, that's all I can do by myself.

IMHO, that's something that needs to be treated in the massive
replication work planned for 8.5.

--
Guillaume

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Markus Wanner 2009-05-28 15:52:02 Re: PostgreSQL Developer meeting minutes up
Previous Message Robert Haas 2009-05-28 15:46:58 Re: PostgreSQL Developer meeting minutes up