Recover after a failed switchover

A failed swithcover attempt left both databases with a DATABASE_ROLE=PHYSICAL_STANDBY

Steps I followed to recover from the failure and to change the old PRIMARY back to PRIMARY was as follows:

SQL>shutdown immediate

ORA-01092: ORACLE instance terminated. Disconnection forced

Login to sqlplus again as sysdba and do a startup mount

SQL>startup mount

ORACLE instance started.

Total System Global Area 6.8947E+10 bytes

Fixed Size                  2189520 bytes

Variable Size            2.0670E+10 bytes

Database Buffers         4.8050E+10 bytes

Redo Buffers              225488896 bytes

Database mounted.

SQL>SELECT DATABASE_ROLE, status,OPEN_MODE,DB_UNIQUE_NAME, PROTECTION_MODE, PROTECTION_LEVEL, SWITCHOVER_STATUS

FROM V$DATABASE, V$INSTANCE

/

DATABASE_ROLE    STATUS       OPEN_MODE            DB_UNIQUE PROTECTION_MODE      PROTECTION_LEVEL     SWITCHOVER_STATUS

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

PHYSICAL STANDBY MOUNTED      MOUNTED              casprd    MAXIMUM PERFORMANCE  MAXIMUM PERFORMANCE  RECOVERY NEEDED

Cancel the MRP process. You may receive “ORA-16136: Managed Standby Recovery not active” if the MRP process is not running.

                                              0

SQL>alter database recover managed standby database cancel;

alter database recover managed standby database cancel

*

ERROR at line 1:

ORA-16136: Managed Standby Recovery not active

Terminate the current switchover to Standby that never completed fully.  

SQL>alter database recover managed standby database finish;

Now switchover to Primary.

SQL>alter database commit to switchover to primary with session shutdown;

Open the database.

SQL>alter database open;

 Confirm DATABASE_ROLE

SQL>SELECT DATABASE_ROLE, status,OPEN_MODE,DB_UNIQUE_NAME, PROTECTION_MODE, PROTECTION_LEVEL, SWITCHOVER_STATUs

FROM V$DATABASE, V$INSTANCE

/

DATABASE_ROLE    STATUS       OPEN_MODE            DB_UNIQUE PROTECTION_MODE      PROTECTION_LEVEL     SWITCHOVER_STATUS

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

PRIMARY          OPEN         READ WRITE           casprd    MAXIMUM PERFORMANCE  MAXIMUM PERFORMANCE  TO STANDBY