Re: Sync Rep: First Thoughts on Code

On Wed, 2008-12-24 at 02:23 +0900, Fujii Masao wrote:

> Oh, sorry. I don't want to scare you ;) But, yes, it's important. We should
> rethink the question? "Why does the failed server always need a fresh
> backup?" Though we discussed it previously and concluded that it should
> be done next time.
> http://archives.postgresql.org/pgsql-hackers/2008-11/msg01612.php

We might ask why pg_start_backup() needs to perform checkpoint though,
since you have remarked that is a problem also.

The answer is that it doesn't really need to, we just need to be certain
that archiving has been running since whenever we choose as the start
time. So we could easily just use the last normal checkpoint time, as
long as we had some way of tracking the archiving.

ISTM we can solve the checkpoint problem more easily and it would
potentially save much more time than "tuning rsync for Postgres", which
is what the other idea amounted to. So I do see a solution that is both
better and more quickly achievable for 8.4.

--
Simon Riggs www.2ndQuadrant.com
PostgreSQL Training, Services and Support