Oracle Active Data Guard has realtime query. Real time query means your physical standby database to be open read-only while Redo data is coming and apply active.
For example You change PROD database
select salary from employees where employee_id=100;
24000
then you change
update employees set salary=10000 where employee_id=100;
commit;
Up-to-date Meantime connect Physical database
select salary from employees where employee_id=100;
10000;
User connected to a physical standby database can query data that is up-to-date with the primary database.
First you must stop redo data applyfor open phy.standby in read only
DGMGRL>edit database orclstby set state=’apply-off’;
then open database
alter database open;
and last restart redo apply
Dgmgrl>edit database orclstby set state=’apply-on’;
