When you execute the flashback database command, Oracle checks to make sure all
required archived and online redo log files are available. If the logs are available, the online
datafiles are reverted to the time or SCN specified.
If there is not enough data online in the archive logs and the flashback area, you will need to
use traditional database recovery methods to recover the data. For example, you may need to use
a file system recovery method followed by rolling the data forward.
Once the flashback has completed, you must open the database using the resetlogs option in
order to have write access to the database:
alter database open resetlogs;
500 Oracle Database 11g DBA Handbook
To turn off the flashback database option, execute the alter database flashback off command
when the database is mounted but not open:
startup mount exclusive;
alter database flashback off;
alter database open;
You can use the flashback options to perform an array of actions??”recovering old data,
reverting a table to its earlier data, maintaining a history of changes on a row basis, and quickly
restoring an entire database. All these actions are greatly simplified if the database has been
configured to support Automatic Undo Management (AUM). Also, note that the flashback database
command requires the modification of the database status. Although these requirements can
present additional burdens to DBAs, the benefits involved in terms of the number of recoveries
required and the speed with which those recoveries can be completed may be dramatic.
Pages:
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756