switch-over database roles..

On primary

select name,open_mode,database_role,db_unique_name,protection_mode from v$database;

alter database commit to switchover to standby;

startup mount;

alter database recover managed standby database disconnect from session;

select name,open_mode,database_role,db_unique_name,protection_mode from v$database;

Now go to the originally standby database

alter database commit to switchover to primary;
alter database open;
select name,open_mode,database_role,db_unique_name,protection_mode from v$database;


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Errors Handled 

SQL> alter database commit to switchover to primary;

SQL> alter database commit to switchover to primary;

alter database commit to switchover to primary

*

ERROR at line 1:

ORA-16139: media recovery required

SQL> SELECT SWITCHOVER_STATUS FROM V$DATABASE;

SWITCHOVER_STATUS

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RECOVERY NEEDED

SQL> RECOVER MANAGED STANDBY DATABASE FINISH;

Media recovery complete.

SQL> alter database commit to switchover to primary;

Database altered.

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If you get an error in the above command like

ORA-01093: ALTER DATABASE CLOSE only permitted with no sessions connected

Did followng and worked fine for me

select switchover_status from v$database;

select sid, process, program from v$session where type = 'USER';

alter database commit to switchover to primary with session shutdown;

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