Real-Time Apply is Enabled / Disabled

How to check real-time apply is enabled or not on Physical Standby Database

To start the real time apply (standby redo logfiles are must for it)

On Physical Standby
--------------------- 
SQL> select DEST_ID,dest_name,status,type,srl,recovery_mode 
from v$archive_dest_status;

   DEST_ID DEST_NAME               STATUS    TYPE           SRL RECOVERY_MODE
---------- ----------------------- --------- -------------- --- --------------
         1 LOG_ARCHIVE_DEST_2       VALID     LOCAL          NO  MANAGED

SQL>
alter database recover managed standby database disconnect from session;

On Physical Standby
--------------------- 
SQL> select DEST_ID,dest_name,status,type,srl,recovery_mode 
from v$archive_dest_status;

 DEST_ID DEST_NAME             STATUS    TYPE      SRL RECOVERY_MODE
-------- -------------------- --------- --------- --- ---------------
     1 LOG_ARCHIVE_DEST_2    VALID     LOCAL     YES  MANAGED REAL TIME APPLY

SQL>

alter database recover managed standby database using current logfile 
disconnect from session;