Re: why r more archives generated during hot backup

Jonathan Lewis wrote:
>
> Connor,
>
> You don't need to verify it, you've got the
> seminar notes (Session 03 Redo: slide 25
> IIRC).
>
> You have to be careful about saying things
> like 'flushed out by dbwr' - it might give the
> wrong impression. If a block is written by DBWR
> it (usually) stays in memory, so it doesn't
> get a full copy image on the next changes.
> If it is flushed because __another_process__
> wants to use the buffer and it is subsequently
> re-read then, as you point out, the first update
> thereafter writes two redo record again - the full
> block image, and then the normal redo vector.
>
> --
> Regards
>
> Jonathan Lewis
> http://www.jlcomp.demon.co.uk
>
> Next Seminar dates:
> (see http://www.jlcomp.demon.co.uk/seminar.html )
>
> ____England______September 24/26, November 12/14
>
> ____USA__________November 7/9 (MI), 19/21 (TX)
>
> The Co-operative Oracle Users' FAQ
> http://www.jlcomp.demon.co.uk/faq/ind_faq.html
>
> Connor McDonald wrote in message <3D8F5CD0.3E69_at_yahoo.com>...
> >
> >I haven't physically sat down and verified, but I think its (only) the
> >*first* change to the block since it is loaded into the cache. Thus you
> >might get (all in hot bkp mode)
> >
> >- change block (whole block to redo)
> >- change again (just rows to redo)
> >- flushed out by dbwr
> >- change same block (whole block)
> >- change again (just rows)
> >

Knew I'd seen it somewhere...Apologies for not providing appropriate acknowledgement.

Cheers
Connor

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

http://www.oracledba.co.uk

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