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Re: backup & recovery

From: Martin Haltmayer <Martin.Haltmayer_at_0800-einwahl.de>
Date: 2000/06/21
Message-ID: <39509DA2.A0984C0@0800-einwahl.de>#1/1

I think there is a small confusion. I did not mean the flush of the redo log buffers. The flush to redo log is not prohibited (and to my knowledge cannot be prohibited after a commit).

I meant the flush of dirty db buffers. They *are* flushed when you do a log switch. But before that event and before a checkpoint they most likely are not unless DBWR decided to do so to regain some buffers.

Martin

Eugenio wrote:
>
> How can you set your instance to avoid that redo info are flushed before log
> switch ?? and why ??
> Can you do it using undocumented parameters or with standard instance
> parameters ??
>
> thanks
> --
> be happy
>
> Eugenio
> remove _nospam from reply address
>
> Opinions are mine and do not necessarily reflect those of my company
>
> =======================================================
> Martin Haltmayer wrote in message <39462D1C.49EB6E99_at_0800-einwahl.de>...
> >Precisely. Because your information to roll forward is stored in your
 online
> >redo log. If you lost it and if it is not flushed to disk how do you want
 to
> >restore it?
> >
> >Martin
> >
> >
> >
> >Alvin wrote:
> >>
> >> Really??
> >> if i do recover database in database mounted status,
> >> those data in redo log can't be rollforward??
> >>
> >> Alvin Huang
> >>
> >> Martin Haltmayer ¼¶¼g©ó¤å³¹ <39392476.5A4CCF7B_at_0800-einwahl.de>...
> >> >Yes, you can loose data even if did not use "nologging" operations.
> >> >
> >> >Do the following:
> >> >
> >> >alter system switch logfile;
> >> ><do some transactions that are committed but not yet flushed to disk by
 DBWR.
> >> >You can achieve this by setting your logging options so high that no
 data
 is
> >> >flushed before a redo log switch. >
> >> >shutdown abort
> >> >
> >> >Then physically remove all members of the group of the current redo log.
> >> >
> >> >There is no way to replay the lost current redo log's entries.
> >> >
> >> >Martin
> >> >
> >> >
> >> >
> >> >zameer2_at_my-deja.com wrote:
> >> >>
> >> >> Hi,
> >> >>
> >> >> In archive log mode is there any chance that you might loss committed
> >> >> data ?
> >> >>
> >> >> Thanks for your feedback.
> >> >>
> >> >> Zameer
> >> >>
> >> >> Sent via Deja.com http://www.deja.com/
> >> >> Before you buy.
> >> >
> >> >
Received on Wed Jun 21 2000 - 00:00:00 CDT

Original text of this message

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