Active dataguard means, the standby database is open with read only mode, even when redo logs are getting applied in real time.

Below are the benefit of using active dataguard.

  1. Reporting queries can be offloaded to standby database.
  2. Physical block corruptions are repaired automatically either at primary or physical standby database.
  3. RMAN backups can be initiated from standby , instead  of primary which will reduce cpu load from primary.

NOTE – To use active dataguard, you need additional license from oracle

Let’s say we have a physical standby database which is in mount state. Implement below steps to enable active dataguard database.

 

1. Cancel the media recovery on physical standby.

SQL> alter database recover managed standby database cancel;

2. Open the database[PHYSICAL STANDBY]

SQL> alter database open;

Database altered.

3. Start media recovery with real-time log apply[PHYSICAL STANDBY]

SQL> alter database recover managed standby database using current logfile disconnect from session;

Database altered.

4. Check the database status:[PHYSICAL STANDBY]

SQL> select name,open_mode from v$database;

NAME      OPEN_MODE
--------- --------------------
PRODDB   READ ONLY WITH APPLY



SQL> select process,status,sequence# from v$managed_standby;

PROCESS   STATUS        SEQUENCE#
--------- ------------ ----------
ARCH      CONNECTED             0
ARCH      CONNECTED             0
ARCH      CONNECTED             0
ARCH      CONNECTED             0
ARCH      CONNECTED             0
RFS       IDLE                  0
RFS       RECEIVING           510
RFS       IDLE                  0
RFS       IDLE               4178
MRP0      APPLYING_LOG        510 --->>>>  MRP PROCESS

Now active dataguard has been enabled.