Data Guard Flashback database Tips Oracle Tips by Burleson Consulting December 9, 2011

Oracle Data Guard Flashback Database

Flashback database is an alternate solution to point-in-time recovery (PITR). A PITR with Flashback database allows the restoration of a database from the flashback logs and archived redo log files. This is not a default feature, so the primary and standby databases will need to be configured to use the flashback database functionality.

Once Flashback database configured, any change made on the primary database is recorded in the flashback recovery area in the form of change vectors or flashback logs. There are two important advantages of using the flashback database in conjunction with Data Guard. The two advantages are as follows:

• It removes the necessity of adding delay in the log apply service in order to avoid any corruption of the Oracle instance due to user errors. If a data error is propagated to a standby database, the Oracle instance can be re-created to a point in time just prior to when the error occurred, and a switchover can be performed to recover the overall situation. Similarly, the primary database can be flashed back to a point in time in order to remove the transactions containing data error. In the previous version of Oracle database, correcting this situation would have required a switchover and re-creation of the primary databases.
  

• Configuring the flashback database feature on the primary database removes the need for recreating the database after a failover operation. It can simply be flashed back to a point in time just prior to the failover and all archived redo log files applied to roll forward.
  

• In case of media failure, it may not be possible to flashback without recovering the affected data files. In this scenario, a combination of traditional tablespace point-in-time recovery and flashback database technology will be very useful to achieve a fast recovery.

For more information regarding flashback technology, refer to the documentation.