A brief history about Oracle Flashback , its starting version, various enhancements, What it uses to manage the flashback.
| Version | Flashback Option available | Provides | Uses | Depends on |
| 9i | Flashback Query | allows the user to query the data at some point-in-time in the past to reconstruct the lost data that may have been deleted or changed by accident | Undo | undo_retention |
| 10g | Flashback Version Query | provides a mechanism to view changes made to the database over the time at row level | undo | undo_retention |
| 10g | Flashback Transaction Query | provides a mechanism to view changes made to the database at the transaction level , dba_transaction_query you can view the versions of statements for that transactions and revert to particular statement | undo | undo_retention |
| 10g | Flashback Table | provides the ability to recover a table, a set of tables to the specific point in time | undo | undo_retention |
| 10g | Flashback Drop | provides a safety net when dropping objects as you can very quickly and easily undo the drop | recyclebin | recyclebin on |
| 10g | Flashback database | is a new strategy for doing point-in-time recovery. It quickly rewinds an Oracle database to a previous time to correct any problems cause by logical data corruption or by human mistakes | flashbacklogs and uses rvwr bg process |
flashback area |
| 10g | Flashback Standby Database | This flashback feature improves the switchover and failover time of a standby database. You no longer need to specify a log apply delay, because you can now roll back the standby database if an error occurs on the primary and is propagated to the standby. Useful when there is a logical corruption to avoid same propagated to standby | flashback logs/archives | delay option with automatic recovery recover managed standby database delay 60 disconnect; |
| 10g | Flashback Reinstantiation | This flashback feature reduces the need to instantiate the old primary database following a failover. This in turn lets you restore full resiliency after a failure more quickly. You can do this by using the SQL statement FLASHBACK DATABASE to roll back the primary database in time to synchronize with the standby database. | select standby_became _primary_scn from v$database; |
flashback old primary to the scn came from standby (current primary) |
| 11gR1 | Flashback Data Archive
(Total Recall) |
provides support for querying the history data using the familiar flashback feature (flash back query) with sql construct clause “AS of”, beyond the undo retention or flash back archive limit | A separate flashback archive tablespace and uses fdba bg process | object clause Retention alter table employees flashback archive <ts>; |
Hope this helps, this information is gathered from different sources and updated here in, if any of above seems inaccurate please update me , will correct the same.
-Thanks
Geek DBA
Follow Us!