Switch Over-Role Transition-Oracle Dataguard

              Switch Over-Role Transition-Oracle Dataguard

Switch over is planned role transition of Oracle dataguard. It's used for production planned maintenance task etc.

Step-1:

Verify there are no redo transport error or redo gap at standby database.

SQL> select STATUS,GAP_STATUS from V$ARCHIVE_DEST_STATUS where DEST_ID=2;

STATUS                                               GAP_STATUS

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

VALID                                                    NO GAP

Step-2:

Verify that target standby database is ready for switch over:

Let 

PRIMARY => DB_UNIQUE_NAME=>PRIMARY

PHYSICAL STANDBY=>DB_UNIQUE_NAME=>STNDBY

SQL> alter database switchover to stndby verify;

(Redo apply must be running before switchover operation)

Step-3:

Initiate Switch Over:

SQL> alter database switchover to standby;

Step-4:

Open the new primary database;

SQL> alter database open;

Step-5:

Mount the new physical standby database:

SQL> startup mount;

Step-6:

Start redo apply on the physical standby database:

alter database recover managed standby database disconnect from session;