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Home -> Community -> Mailing Lists -> Oracle-L -> Re: not including temp neither undo tablespace in full backup
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undo tablespace backup is not an option , it is mandatory. Scenario I described earlier, is just one of many possible scenarios, NOT the only scenario..
Here is another scenario for you:
Let us consider the database is in archivelog mode. Cold backup on Sunday (Incorrectly undo data files have not been backed up) Tuesday evening, point-in-time recovery as of 4PM needed. Restore the cold backup, make the undo files offline, recover database until 4PM. At this point, you can not open the database. Since undo tablespaces were not restored, no redo will be applied to undo tablespaces. That means, there may be many transactions outstanding inthe database [Oh, yes, even if you comment undo segments, oracle knows about the segments]. Instance recovery can not access the undo segments that were active at 4PM and so instance recovery can NOT complete. Instance will either crash right after the open/ or will not allow you to open (version specific, controlled by few parameters).
Database is in corrupted state!!! Backup is useless.
In almost, every scenario, instance recovery can NOT complete without undo segments.
If you don't want to take undo tablespace backup, then, following are the rules:
Risk is so huge, just backup undo tablespace also.
Thanks
Riyaj "Re-yas" Shamsudeen
Certified Oracle DBA (ver 7.0 - 9i)
Allocation & Assortment planning systems
JCPenney
Juan Carlos Reyes Pacheco wrote:
>Riyaj, First I need to clarify I'm not advicing it, this is only one idea I had.
>Well, I t hink I'll do the test tomorroy, but what do you think
>about this idea,
>
>shutdown immediate
>startup
>shutdown immediate;
>I think this will solve (in theory) the situation you says or I'm wrong.
>
>
>
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-- http://www.freelists.org/webpage/oracle-lReceived on Thu Oct 13 2005 - 08:01:55 CDT
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