Enabling Flashback Database in Oracle

Oracle Flashback Database, allows to quickly recover the entire database from logical data corruptions or user errors. It is very similar to PITR (Point In Time Recovery) which puts back the database to a state at a particular time in recent past. However, Flashback Database is much faster than PITR as it does not require restoration of datafiles from the backup. It only requires applying fewer changes from the archived redo logs.

Flashback database can be enabled by following the below steps but before that you need to make sure of the 2 things: Your database needs to be in archivelog mode and you must have FRA(flash recovery area) for your database because the Flashback logs can be stored only in FRA.

Steps to enable Flashback Database:

1. Place your database in mount stage.

• sql>shutdown immediate
• sql>startup mount

2. Set DB_FLASHBACK_RETENTION_TARGET to the requried minutes to have the flashback window. By default, the value would be 1440 minutes (1 day)

• sql>alter system set db_flashback_retention_target=7220; #Here I have set it to 5 days

3. Enable Flashback on the database

• sql>alter database flashback on;

4. You can skip enabling flashback at tablespaces level as shown below

• sql>alter tablespace users flashback off;

5. Finally open the database

• sql>alter database open;

6. You can check if the database is enabled with Flashback or not

• sql>select flashback_on from v$database;

FLASHBACK_ON

——————

YES

Here you go !!!

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