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Re: rman duplication question

From: Chuck <>
Date: Tue, 13 Nov 2007 14:34:54 GMT
Message-ID: <iCi_i.5725$Vp3.1860@trnddc05>

Jerome Vitalis wrote:
> On Mon, 12 Nov 2007 15:11:48 +0000, Chuck wrote:

>> Shouldn't this work? I mean, doesn't the duplicate process only need an
>> undo (any undo) to make the aux db transactionally conistent for
>> recovery?

> RMAN duplicate cannot do that. You can exclude some tablespaces during
> the duplication but this is not possible with SYSTEM or UNDO tablespaces.
> I suggest you perform a plain RMAN restore and recovery on your
> development host with your production database backups. With these
> commands, RMAN allow you to exclude UNDO tablespaces.
> The only requirement is that your backup must be a consistent (offline)
> one.
> You will use something like that in your RMAN incomplete recovery job:
> ...
> set until ...
> restore database skip forever tablespace undotbs1;
> recover database skip forever tablespace undotbs1 noredo;
> ...
> You will have to temporarily switch back to good old rollback segments to
> be able to create your tiny UNDO tablespace, as explained by Tom Kyte
> here:
> Jerome

I haven't tried it yet but I think you are right. What it comes down do is "what exactly is in the redo logs". When you update a table block, obviously the changes to that block get logged. But you also update an undo block. The question is "does the undo block change also get logged"? If the answer is yes (and I think it is) then what I want to do would not be possible.

Theoretically though there should be no need to log the undo. It could be regenerated while rolling forward transactions into whatever undo tablespace I pick in the AUX db. I will have to read up on this again as a refresher on the exact contents of the redo logs.

How I wish they would let me update these databases to 10g where I could just use data pump and be done with it. Received on Tue Nov 13 2007 - 08:34:54 CST

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