Re: ORACLE Backups

In article: <1994Aug18.152944_at_ittpub> verbrugge_at_nl101.ittpub.nl (Bob Verbrugge - ITT Gouden Gids) writes:
>
>
> Correct, furthermore it reads (18-8):
>
> nerver perform a full database backup after an instance failure or after
> the database is shutdown with immediate or abort priority (that is, using
> a SHUTDOWN IMMEDIATE or SHUTDOWN ABORT statement).
>
> Bob.
> --
>
>
> In article <32vif0$4as_at_stc06.CTD.ORNL.GOV>, bzy_at_ornl.gov ( B C Zygmunt)
 writes:
> > In article 777144673snz_at_keithl.demon.co.uk, Keith_at_keithl.demon.co.uk (Keith
 Leng) writes:
> >> In article <32b6pl$506_at_larch.cc.swarthmore.edu>
> >> stauffer_at_cc.swarthmore.edu "R Glenn Stauffer" writes:
> >>
> >> > bzy_at_ornl.gov writes:
> >> > >
> >> > >
> >> > > Once you do the "shutdown abort", you should bring the database back up

 again > > and do a regular shutdown. Then do your file backups.


> >> > > 

> >> > > Beverly

> >> > > 

> >> > 

> >> > Why is this?   ....

> >> 

> >> Good question. I don't follow the logic of the above advice myself. What 

> >> difference does it make if you do the startup on the database as it stands

> >> immediately before you do a backup or immediately after a restore? In either

> >> case you are running the startup against exactly the same files, so, surely,

> >> you will get exactly the same result.


> >> 

> >> Keith

> > 

> > 

> > The reason I gave this advice can be found in the Oracle documentation. It

> > may be in earlier versions, but the one I'm looking at now is "Oracle7 Server

> > Administrator's Guide", page 18-7.

> > 

> > "A full backup cannot be taken if the database is open or has been shut down

> > because of an instance failure or abort; in such cases, a backup is not a full

> > backup because the files are not consistent with respect to the current point-

> > in-time."

> > 

> > 

> > +                                 


I agree that it is good practice, and it is advice that I would follow myself. But I still think that the result would be the same whether the start-up was done before a backup or after a restore. I don't understand what the manual is saying in that quote. I would be grateful to anyone who can enlighten me. The backup includes the control and log files so I can see no reason why the recovery procedures wouldn't work after a restore. As far as I know, the timestamps on the various header blocks must be consistent with each other, but have no relation to "the current point in time".