Re: PITR Phase 2 - Design Planning

On Tue, 2004-04-27 at 23:11, Rod Taylor wrote:
> On Tue, 2004-04-27 at 17:36, Simon Riggs wrote:
> > On Tue, 2004-04-27 at 21:56, Rod Taylor wrote:
> > > > Overall, I'd refer back to the points Bruce raised - you certainly do
> > > > need a way of finding out the time to recover to, and as others have
> > > > said also, time isn't the only desirable "recovery point".
> > >
> > > Wouldn't it be sufficient to simply use the transaction ID and ensure
> > > that all the parameters the user might want to use to find that ID can
> > > be made available in the log files?
>
> > Yes, of course, all methods of locating a particular xlog file to stop
> > at are effectively equivalent. The discussion is mostly about what is
> > convenient for the user in a real recovery situation.
>
> I see.. The first thing I would need to do is look at /var/log/pgsql. At
> that point it really doesn't matter what the identifier is so long as
> the identifier is there.
>

PITR works on the assumption that /var/log/pgsql no longer exists at
all. It is suitable for use in bare-metal recovery situations, as well
as usage-induced situations.

You pick up the pieces, work out what the best identifier is, then plan
on using that.... might not be a pgsql log, it might be:
i) literally wallclock - "power went off about 2"
ii) other systems logs
iii) etc

Best Regards, Simon Riggs