Enabling force logging

Perform the following steps on the primary database:

1. Check the force logging status as follows:

   SQL> select name, force_logging from v$database;
   NAME      FOR
   --------- ---
   ORCL      NO
   

2. Enable the force logging mode as follows:

   Enabling Force Logging on Primary Database is mandatory. 
   SQL> alter database force logging;
   Database altered.
   

3. Check the force logging status again as follows:

   SQL> select name,force_logging from v$database;
   NAME      FOR
   --------- ---
   ORCL      YES
   

   In the alert log, you'll see following lines:

   alter database force logging
   ALTER DATABASE FORCE LOGGING command is waiting for existing direct writes to finish. This may take a long time.
   Completed: alter database force logging

          4. Disable the force logging mode as follows:

SQL> alter database no force logging;
Database altered.