Oracle Turn on Flash back

1. To see if the database is an archive mode:
   

Sql> Show parameter Db_flashback;

NAME TYPE VALUE

------------------------------------ ----------- ------------------------------

Db_flashback_retention_target integer 1440

sql> archive log list;

Database Log Mode Archive mode

Automatic Archival Enabled

Archive DESTINATION/ORADATA/ARCH/MATRIXDG

Oldest online log sequence 65

Next log sequence to archive 0

Current Log Sequence 67

2. Set the Flash back parameter:

Sql> Show parameter db_recovery;

NAME TYPE VALUE

------------------------------------ ----------- ------------------------------

Db_recovery_file_dest String/u2/oracle/fast_recovery_area

Db_recovery_file_dest_size Big Integer 4122M

As above: Db_recovery_file_dest is the flashback path and the db_recovery_file_dest_size is the size of the Flash back zone.

Sql> Show parameter Flashback;

NAME TYPE VALUE

------------------------------------ ----------- ------------------------------

Db_flashback_retention_target integer 1440

such as: Db_flashback_retention_target Flash back retention time

3. Turn off the database and enable Flash back

Sql>shutdown Immediate

Sql>startup Mount

Sql>alter database flashback on;

Sql>alter database open;

4. Query Flashback Status

Sql> select flashback_on from V$database;

flashback_on

------------------

YES

Oracle Turn on Flash back