Which two statements are true about Real-Time Query?
A.
Setting STANDBY_MAX_DATA_DELAY =0 requires synchronous redo transport.
B.
Disabling Real-Time Query prevents the automatic start of redo apply when a physical standby database is
opened READ ONLY.
C.
Real-Time Query sessions can be connected to a Far Sync instance.
D.
Real-Time Query has no limitations regarding the protection level of the Data Guard environment.
E.
A standby database enabled for Real-Time Query cannot be the Fast-Start Failover target of the Data
Guard configuration.
Explanation:
If a license for the Oracle Active Data Guard option has been purchased, Redo Apply can be active while the
physical standby database is open, thus allowing queries to return results that are identical to what would be
returned from the primary database. This capability is known as the real-time query feature.
Incorrect Answers:
A: If STANDBY_MAX_DATA_DELAY is set to 0, a query issued to a physical standby database is guaranteed
to return the exact same result as if the query were issued on the primary database, unless the standby
database is lagging behind the primary database, in which case an ORA-3172 error is returned.
Note: The STANDBY_MAX_DATA_DELAY session parameter can be used to specify a session-specific apply
lag tolerance, measured in seconds, for queries issued by non-administrative users to a physical standby
database that is in real-time query mode. This capability allows queries to be safely offloaded from the primary
database to a physical standby database, because it is possible to detect if the standby database has become
unacceptably stale.
Correct Ans: A, D
Setting STANDBY_MAX_DATA_DELAY=0 must requires synchronous redo transport.
Incorrect: Disabling Real-Time Query prevents the automatic start of redo apply when a physical standby database is opened READ ONLY.
Real-time QUERY and Real-time APPLY are not the same.
Explanation:
The following restrictions apply if STANDBY_MAX_DATA_DELAY is set to 0 or if the ALTER SESSION SYNC WITH PRIMARY SQL statement is used:
* The standby database must receive redo data via the SYNC transport.
* The redo transport status at the standby database must be SYNCHRONIZED and the primary database must be running in either maximum protection mode or maximum availability mode.
* Real-time apply must be enabled.
When using the Oracle Data Guard broker, it is not necessary to stop Redo Apply and restart Redo Apply when enabling real-time query. Real-time query is not the same as real- time apply.
A,D