Re: backup UNDO Tablespace (dba_undo_extents)

The undo tablespace is required for database recovery

Sent from my iPhone
On Dec 15, 2009, at 8:51 AM, "Guillermo Alan Bort" <cicciuxdba@xxxxxxxxx> 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@xxxxxxxxx> 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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