Oracle Database 12c: RAC Administration — Question 38

Examine this tnsnames entry from a RAC configuration using a SCAN listener:
HR=(DESCRIPTION=
(LOAD_BALANCE =on)
(ADDRESS=(PROTOCOL=TCP)(HOST=cluster01-scan)(FORT=1521))
(CONNECT_DATA=(SERVICE_NAME=HRSRV)))
Which two statements are true about clients using this entry to connect? (Choose two.)

Answer options

• A. The host name in the tnsnames entry must be changed if nodes are added or removed from the Cluster.
• B. Clients using EZConnect can benefit from connect time load balancing because the tnsnames entry refers to a SCAN listener.
• C. Client connection requests are automatically balanced across all IP addresses defined for the SCAN.
• D. A client connection request is received by a SCAN listener that creates the connection to the least-loaded database instance.
• E. Client connection requests are automatically failed over to another SCAN listener if the chosen SCAN listener is not available.

Correct answer: B, D

Explanation

Option B is correct because the SCAN listener allows EZConnect clients to achieve connect-time load balancing. Option D is also correct as the SCAN listener routes requests to the least-loaded instance. Options A and C are incorrect since the hostname does not need to change with node modifications, and client requests are not automatically balanced across IPs; rather, the SCAN listener manages the load. Option E is not applicable here since the scenario only addresses connection creation and not failover mechanisms.