How to open Standby database in snapshot mode for Oracle

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.