Which three are required in order to use Real-Time Query without lagging behind the primary?
A.
There must be standby redo logs on the standby database.
B.
There must be standby redo logs on the primary database.
C.
The primary must ship redo asynchronously.
D.
COMPATIBLE must be set to 11.1.0 or higher.
E.
Real-Time apply must be enabled on the standby.
Explanation:
D: The COMPATIBLE database initialization parameter must be set to 11.0 or higher to use the real-time query feature of the Oracle Active Data Guard option.
E: The apply lag control and Redo Apply synchronization mechanisms require that the client be connected and issuing queries to a physical standby database that
is in real-time query mode.
Incorrect Answers:
C: The standby database must receive redo data via the SYNC transport.https://docs.oracle.com/cd/E11882_01/server.112/e41134/manage_ps.htm#SBYDB00707
10.2.1.2 Configuring Apply Lag Tolerance in a Real-time Query Environment
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.
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.
10.2.1.3 Forcing Redo Apply Synchronization in a Real-time Query Environment
SQL> ALTER SESSION SYNC WITH PRIMARY;
The following additional 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.
A,D,E
A, D and E.
Real-Time Query is a feature from 11g.