Re: Oracle 8i (8.1.7.0.1) + Redhat Linux 7.2 = Cannot create tablespace file > 2 gb

"Howard J. Rogers" wrote:
>
> We were. Recover until time 10.00am, when you were told Scott dropped the
> SALES table. Open resetlogs. Bugger me.... SALES is still missing.
>
> Now repeat the incomplete recovery.
>
> You can restore the datafiles, for sure. But your control file now thinks
> its time 0. Your online redo logs think likewise.
>
> IE, before the recovery, you had:
>
> Control: time M
> Datafiles: time M
> Online Redo : time M
>
> Restore the datafiles:
>
> Control: M
> Datafiles: F
> Online Redo : M
>
> Perform Recovery:
>
> Control : M
> Datafiles : L
> Online Redo : M
>
> Open resetlogs:
>
> Control : A
> Datafiles : A
> Online Redo: A
>
> Now repeatr the recovery....
>
> Control A
> Datafiles F
> Online redo A.
>
> Your control file and redo logs are from a time *before* the datafiles.
> Rather worse, they are from a completely different incarnation of the
> database. You won't be able to repeat the recovery.

Sure you can... just recreate the controlfile and delete the online redo logs. Re-restore your datafiles, and you're off and running again.

> However, if you've backed up the original control files and redo logs first,
> then given:
>
> Control: A
> Datafiles: A
> Online Redo : A
>
> You can restore the precautionary backup, to give this:
>
> Control : M
> Datafiles: A
> Online Redo : M
>
> Now re-restore the datafiles:
>
> Control : M
> Datafiles: F
> Online Redo : M
>
> And "M-F-M" is the state we were in to perform the initial recovery. So now
> you can recover until time "K".
>
> Without being able to restore the initial control files or online redo logs,
> you cannot repeat an incomplete recovery if it proves that the first attempt
> sailed straight past the dodgy redo.

That's not correct. First of all you can just throw away your online redo logs if you're doing an incomplete recovery - they're worthless since they contain information newer than the point to which you're recovering. So the online redo part of your argument doesn't stand up. As for the controlfile, just recreate it like I said in my last post.

> > Sure there is! Just re-restore your backup, and start again. Might
> > cost you some time if the DB is big, but certainly possible.
>
> You can't do that.

Sure I can, and I have more than once!

> If you restore the datafiles from the "proper" backup,
> you are stuck with a control file and online logs from a new incarnation.

So what? Blow 'em away, recreate the controlfile, and I'm fine.

> If
> you restore *everything* from the previous backup, you've possibly lost
> transactions in the current log you wanted to re-perform.

Transactions in the current log? We're talking incomplete recovery here - we never get to the online redos. Why do we need them? Delete them, and let the next open resetlogs re-recreate them.  

> 'Fraid the manuals are unambiguous on the subject, as be me: if you don't
> take a precautionary backup of your control files and online logs before
> beginning an incomplete recovery, you cannot repeat said recovery when you
> find that it didn't bring back what you wanted it to.

I totally disagree - UNLESS you're talking about an incomplete recovery to an extremely recent point in time, so recent that there is still data in the online redos that you're rolling forward onto. But I was pretty sure we were talking about rolling back in time a few hours/days/weeks, where we only apply *archived* redo to catch up. But in general, for an incomplete recovery, Oracle never even reads the online redo logs, so it will never complain that they're from a different time or incarnation.

Regards,
Sean Received on Sat Jun 29 2002 - 00:35:47 CDT