Step:1 In standby database check the database role and open_mode
SQL> SELECT OPEN_MODE,PROTECTION_MODE,DATABASE_ROLE FROM V$DATABASE;
OPEN_MODE PROTECTION_MODE DATABASE_ROLE
-------------------- -------------------- ----------------
READ ONLY WITH APPLY MAXIMUM PERFORMANCE PHYSICAL STANDBY
Step:2 Check archive log gap sequence
SQL> SELECT THREAD#, LOW_SEQUENCE#, HIGH_SEQUENCE# FROM V$ARCHIVE_GAP;
no rows selected
Step:3 Cancel MRP process in standby database
SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;
Database altered.
Step:4 Bring up standby database as primary
SQL> alter database recover managed standby database finish;
Database altered.
SQL> alter database activate standby database;
Database altered.
Managed recovery process has been stopped between primary and standby database and standby becomes primary database.
Step:5 Shutdown and startup database and verify database name its open mode and its role.
SQL> shutdown immediate
ORA-01109: database not open
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORA-32004: obsolete or deprecated parameter(s) specified for RDBMS instance
ORACLE instance started.
Total System Global Area 1.6106E+11 bytes
Fixed Size 7653336 bytes
Variable Size 8.1604E+10 bytes
Database Buffers 7.8920E+10 bytes
Redo Buffers 529215488 bytes
Database mounted.
Database opened.
SQL> select open_mode,database_role from v$database;
OPEN_MODE DATABASE_ROLE
-------------------- ----------------
READ WRITE PRIMARY