RE: How to clear UNDOTBS

From: Goulet, Richard <>
Date: Mon, 18 Jan 2010 08:40:26 -0500
Message-ID: <>


    You as a DBA don't clear the undo tablespace any more, that is handled by Oracle and there are really a number of things that can hold onto undo for long periods of time. The first is the setting of UNDO_RETENTION in your database. The second is how long the user keeps things in limbo land, namely not committing. The next is what other sessions are interested in the rollback data that your storing. I know that UNDO can get very large on some systems, almost being twice the actual database, but that's not your fault or that of the RDBMS, but the application designer and the end user. As examples, one database that I managed some years ago had almost 2TB of data and 500MB of undo, while a PeopleSoft system was 10GB of data and 100GB of UNDO. Go figure.  

Dick Goulet
Senior Oracle DBA/NA Team Lead
PAREXEL International  

From: [] On Behalf Of Eriovaldo Andrietta Sent: Monday, January 18, 2010 8:28 AM
Subject: How to clear UNDOTBS


I have an UNDOTBS that is growin up.
How can I do to clear it ?

I donīt need data that is there saved.
I can restart writting the UNDOTBS again.


Received on Mon Jan 18 2010 - 07:40:26 CST

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