Identify the true statement about adaptive parallelism.

Identify the true statement about adaptive parallelism.

A.
It Is turned on by default.

B.
It is turned off by default.

C.
You should always leave the default setting

D.
There is no such thing.

Explanation:
Adaptive Parallelism: The adaptive multiuser algorithm, which is enabled by default,
reduces the degree of parallelism as the load on the system increases. When using the Oracle
Database adaptive parallelism capabilities, the database uses an algorithm at SQL execution time
to determine whether a parallel operation should receive the requested DOP or have its DOP
lower to ensure the system is not overloaded.
In a system that makes aggressive use of parallel execution by using a high DOP, the adaptive
algorithm adjusts the DOP down when only a few operations are running in parallel. While the
algorithm still ensures optimal resource utilization, users may experience inconsistent response
times. Using solely the adaptive parallelism capabilities in an environment that requires
deterministic response times is not advised. Adaptive parallelism is controlled through the
database initialization parameter PARALLEL_ADAPTIVE_MULTI_USER.
Reference: Oracle Database VLDB and Partitioning Guide, 11g Release 2 (11.2), How Parallel
Execution Works
http://docs.oracle.com/cd/E11882_01/server.112/e25523/parallel002.htm#BEIECCDD