#How To Enable Active Dataguard In Physical Standby Database
https://dbaclass.com/article/enable-active-dataguard-physical-standby-database/
# 1- Cancel the media recovery on physical standby.
SQL> alter database recover managed standby database cancel;
# 2- Open the database[PHYSICAL STANDBY]
SQL> alter database open;
Database altered
# 3- Start media recovery with real-time log apply[PHYSICAL STANDBY]
SQL> alter database recover managed standby database using current logfile disconnect from session;
Database altered.
#4- Check the database status:[PHYSICAL STANDBY]
SQL> select name,open_mode from v$database;
NAME OPEN_MODE
--------- --------------------
PRODDB READ ONLY WITH APPLY
SQL> select process,status,sequence# from v$managed_standby;
PROCESS STATUS SEQUENCE#
--------- ------------ ----------
ARCH CONNECTED 0
ARCH CONNECTED 0
ARCH CONNECTED 0
ARCH CONNECTED 0
ARCH CONNECTED 0
RFS IDLE 0
RFS RECEIVING 510
RFS IDLE 0
RFS IDLE 4178
MRP0 APPLYING_LOG 510 --->>>> MRP PROCESS
