The point is that it doesn't need to roll forward. Those dirty buffers were
flushed, together with their rollback blocks, when you switched logs. The
rollback needed to reverse the uncommitted changes is thus readily
available.
Regards
HJR
--
Resources for Oracle: http://www.hjrdba.com
===============================
"jane" <janeyiu_at_optonline.net> wrote in message
news:NIlL7.28121$636.5030654_at_news02.optonline.net...
> I'm puzzled about the following scenario.
> This question is about the inter-workings of online redo log files,
> DBWn, CKPT...on 8i.
> Pls point out anything I said wrong below.
>
> NOARCHIVELOG mode, have a HUGE rollback segment,
> doing LOTS of modifications, SELECTs, but NO COMMITS.
>
> My question is:
> Online redo files will be reused (yes ?), thus CKPT will happen
> and dirty blocks with UNCOMMITED CHANGES in buffer will be
> flushed/written to disk (yes ?).
>
> System crashes now.
>
> So what happens after instance is back up ?
> Since the redo logs have been reused....
> How exactly does Oracle roll-forward and undo the
> UNCOMMITED changes to the disk ?
> Read from RBS ?
>
> Pls be as specific as u possibly can.
> Really appreciated !
>
> jane
>
>
>
>
>
>
Received on Fri Nov 23 2001 - 01:58:24 CST
