Procedure :
Convert Standby Database in Snapshot Standby
1. Check the Database role
SQL > select status,instance_name,database_role,open_mode from v$database,v$instance;
2. Check the current applied log sequence.
SQL > select thread#,max(sequence#) from v$archived_log group by thread#;
3. Cancel the log application in Standby Database and start the database in mount mode
SQL > alter database recover managed standy database cancel;
SQL > startup mount;
4. Convert Standby Base to Snapshot mode
SQL > alter database convert to snapshot standby;
5. Open the database
SQL > alter database open;
Convert Snapshot Database to Standby Database
1. Check the Database role
SQL > select status,instance_name,database_role,open_mode from v$database,v$instance;
2. Shutdown the system and start it in mount mode.
SQL > shutdown immediate;
SQL > startup mount;
3. Convert Snapshot mode to Standby Base
SQL > alter database convert to physical standby;
4. Stop the system and then start it in mount mode
SQL > shutdown immediate;
SQL > startup mount;
5. Check the status of the database.
SQL > select status,instance_name,database_role,open_mode from v$database,v$instance;
Suggestion :
After opening the database, application can be started.
Always check the log sequence number before and after changing the database mode.