Oracle® Database 10g Insider Solutions

Undo Tips from the Trenches

For best practices and to control the retention of undo records, Oracle recommends that your database undo retention period be at least as long as your longest-running query. If you plan to use flashback features to recover your database from human errors, the undo retention period should be equal to or higher than the maximum time duration you want to go back in the past. You must judiciously compare the time needed for flashback operations as well as for longest-running queries and determine an optimal value for the undo retention period. This will in turn help you determine the undo tablespace sizing.

For certain databases, you may want to limit the undo space by establishing user quotas. You can use the Database ...