backup UNDO Tablespace (dba_undo_extents)

From: Roger Xu <>
Date: Tue, 15 Dec 2009 10:20:58 -0600
Message-ID: <>

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)


Any explanation? How do I keep the backup of undo small?

Roger Xu

-- Received on Tue Dec 15 2009 - 10:20:58 CST

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