Oracle Tips   Donald K. Burleson

Oracle9i Undo Tablespaces

One other new Oracle9i storage feature worth mentioning is the concept of an UNDO tablespace. For years, Oracle DBAs have worked diligently to have the proper rollback management structures in place to handle all the "whoops" activity in their database.

Now, Oracle9i eases this burden by offering automatic management of rollback functions through UNDO tablespaces. UNDO tablespaces can either be created when the database is designed or built later. They are implemented through the undo_management configuration parameter.

The idea behind automatic UNDO management is that Oracle controls how many rollback segments are available for use, along with their size. The desired goal is the elimination of rollback waits, extends, and other performance-sapping problems.
 

The above is an excerpt from Oracle Performance Troubleshooting by Robin Schumacher.

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