Re: Database file configuration for backup/recovery

Keith Boulton wrote:
>
> Keith Boulton <kboulton_at_ntlworld.com> wrote in message
> news:V24e8.28567$hM6.3678545_at_news6-win.server.ntlworld.com...
> > failure than in the last 2 hours, so I would go for a checkpoint timeout
> in
> > that case.
> >
> Doh!
>
> Of course, as someone else pointed out, checkpoint timeout is irrelevant to
> this discussion.
>
> I do, however, have a question.
>
> Has anyone actually tested the impact of these parameters on recovery time?
>
> As I said, I have in the past attempted to find a penalty associated with
> larger logs, but always with checkpoint interval set high and checkpoint
> timeout set to 0. While I'm happy enough to believe that my testing matches
> by theorising about limiting factors affecting restart time, I can't help
> wondering if there's something I've missed.
>
> Any suggestions?

I'm coming in late to this to thread so apologies if someone has already posted this detail. From 8.1 onwards, both the 'log_chec...' parms no longer work in a "oh-i-have-expired,do-a-checkpoint" fashion. All they do is ensure that buffers don't that much out of date, so you get data "dribbling" continuously out to the datafiles

hth
connor

-- 
==============================
Connor McDonald

http://www.oracledba.co.uk

"Some days you're the pigeon, some days you're the statue..."