How is data recovery achieved through Oracle flashback?

2 years ago
Liam
2 minutes

The Flashback Recovery feature in Oracle database allows users to restore the database to a specific point in time rather than fully restoring from a backup. Here are the steps to implement Oracle database flashback recovery.

  1. Firstly, ensure that the database has flashback feature enabled. Check if the value of the database parameter DB_FLASHBACK_RETENTION_TARGET is greater than 0. If the value is 0, it means that the flashback feature is disabled. You can use the following command to check the value of this parameter:
  2. Retrieve the ‘value’ and ‘name’ from the v$parameter where the ‘name’ is equal to ‘db_flashback_retention_target’.
  3. If the value of this parameter is 0, you can enable it using the following command:
  4. Set the database flashback retention target to a specific value for both instances.
  5. The value specifies the flashback retention time in minutes.
  6. Make sure the flashback area is large enough to accommodate the required flashback data. You can use the following command to check the current size of the flashback area.
  7. Retrieve the ‘value’ from the ‘name’ column in the ‘v$parameter’ table where the ‘name’ is ‘db_recovery_file_dest_size’.
  8. If the flashback area is insufficient in size, you can use the following command to increase it:
  9. Change the size of the database recovery file destination to the specified value for both the current session and the whole system.
  10. specifies the size of the designated flashback area in bytes.
  11. Restore the database to a specific point in time. This can be achieved by using the following command:
  12. Roll back the database to a previous timestamp.
  13. refers to a specific point in time.
  14. In addition, the database can be restored to a specific system change number (SCN) using the FLASHBACK DATABASE TO SCN command.
  15. Check the recovery results. This can be done by verifying if the database has been restored to the specified time point or SCN, to confirm the success of the recovery.

Please note that Flashback Recovery only applies to databases with flashback logs enabled, and requires the flashback area to be functioning properly. In addition, Flashback Recovery is only applicable for database-level recovery and cannot be used to recover individual tables or objects.

bannerAds