Re: backup UNDO Tablespace (dba_undo_extents)

From: Roger Xu <wellmetus_at_gmail.com>
Date: Tue, 15 Dec 2009 11:17:15 -0600
Message-ID: <eb64345d0912150917t17438f16n447aec74a5b40486_at_mail.gmail.com>

This thread is nothing to do with the reason why we need to backup undo. I just want to backup the undo segments which are required for recovery but not the entire undo datafile. (I know 11g skips commited before image but I am at 10g.) Thanks.

On Tue, Dec 15, 2009 at 11:07 AM, MacGregor, Ian A. <ian_at_slac.stanford.edu>wrote:

> The undo tablespace is required for database recovery
>
> Sent from my iPhone
>
> On Dec 15, 2009, at 8:51 AM, "Guillermo Alan Bort" <cicciuxdba_at_gmail.com>
> wrote:
>
> Short answer... don't take a backup of the undo tablespace... it's not
> required for database recovery.
>
>
>
> Alan.-
>
>
> On Tue, Dec 15, 2009 at 1:20 PM, Roger Xu <wellmetus_at_gmail.com> wrote:
>
>> Good morning,
>>
>> Background: Windows 2003 / Oracle 10g with auto undo (8K block size)
>>
>> We have only one datafile (20 GB) in the undo tablespace.
>> When I ran RMAN backup of this datafile, it created a 20GB backupset file.
>>
>>
>> I query dba_undo_extents and it shows less than 80 MB used.
>>
>> SQL> select sum(blocks) from dba_undo_extents;
>> SUM(BLOCKS)
>> -----------
>> 9824
>>
>> Any explanation? How do I keep the backup of undo small?
>>
>> Thanks,
>> Roger Xu
>>
>>
>>
>
>

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Received on Tue Dec 15 2009 - 11:17:15 CST