Examine the parallel parameters for your instance.
All parallel execution servers are available and the session use default parallelism settings.
In which two cases will the degree of parallelism be automatically calculated?
A.
Statements accessing tables whom dictionary DOP is 2 or more
B.
Statements accessing tables whose dictionary DOP is DEFAULT
C.
Statements that are estimated to execute for more than 10 seconds serially
D.
Statements accessing tables with any setting for Dictionary DOP
E.
Statements with parallel hints
Explanation:
Note: In earlier versions of the Oracle Database, we had to determine the DOP
more or less manually, either with a parallel hint or by setting a parallel degree with alter table.
There was an automatic computation of the DOP available for the objects with dictionary DOP of
default, derived from the simple formula CPU_COUNT * PARALLEL_THREADS_PER_CPU.
for me, B & C should be correct
for me too. It should be B and C
I guess the parameter show in question are wrong type.
I suppose that
parallel_degree_limit = CPU
parallel_degree_policy = LIMITED
Errata: I’m not sure that C is correct because PARALLEL_MIN_TIME_THRESHOLD of 10 seconds is only available when PARALLEL_DEGREE_POLICY is AUTO.
I think some values are printed in the wrong order: PARALLEL_DEGREE_POLICY can’t be CPU and PARALLEL_EXECUTION_MESSAGE_SIZE can’t be LIMITED!
I assume the POLICY=LIMITED which still makes B & C correct, because LIMITED is exactly the same as AUTO, apart from the fact that Statement Queuing and In-Memory Parallel execution are disabled, so the PARALLEL_MIN_TIME_THRESHOLD is also still applicable.
http://docs.oracle.com/cd/E18283_01/server.112/e17110/initparams177.htm
PARALLEL_DEGREE_POLICY = LIMITED
http://docs.oracle.com/cd/E18283_01/server.112/e17110/initparams177.htm
LIMITED
Enables automatic degree of parallelism for some statements but statement queuing and in-memory Parallel Execution are disabled. Automatic degree of parallelism is only applied to those statements that access tables or indexes decorated explicitly with the PARALLEL clause. Tables and indexes that have a degree of parallelism specified will use that degree of parallelism.
Based on this D and E are correct.
After reading this more carefully I can say that B is correct.
Also C seems to be correct
E can be also correct if hint PARALLEL will be used with attribute AUTO
PARALLEL_MIN_TIME_THRESHOLD specifies the minimum execution time a statement should have before the statement is considered for automatic degree of parallelism. By default, this is set to 10 seconds. Automatic degree of parallelism is only enabled if PARALLEL_DEGREE_POLICY is set to AUTO or LIMITED.