Rolling back or undoing changes in Oracle

You can roll back or undo changes in Oracle by using the AUTO UNDO management option. It is recommended that you use this option. This avoids manual monitoring of UNDO segments.

If a server is upgraded from a previous version of Oracle, set the UNDO_MANAGEMENT=AUTO parameter in init<SID>.ora. Your database administrator needs to determine the UNDO_RETENTION setting. Ensure that the file system which has the UNDOTBS1 tablespace has enough space to use the AUTOGROW setting.