Examine the parallelism parameters for you instance.
Now examine the DSS_PLAN with parallel statement directives:
Which two are true about the DSS_PLAN resource manager plan?
A. URGENT_GROUPS sessions will always be dequeued before sessions from other groups.
B. OTHER_GROUPS sessions are queued for maximum of six minutes.
C. ETL_GROUP sessions can collectively consume 64 parallel execution servers before queuing starts for this consumer group.
D. An ETL_GRP sessions will be switched to URGENT_GROUPS if the session requests more than eight parallel executions servers.
E. URGENT_GROUP sessions will not be queued if 64 parallel execution servers are busy because their PARALLEL_TARGET_PERCENTAGE is not specified.
Correct Answer: AB
Explanation/Reference:
B:PARALLEL_QUEUE_TIMEOUT
Parallel Queue Timeout
When you use parallel statement queuing, if the database does not have sufficient resources to execute a parallel statement, the statement is queued until the required resources become available. However, there is a chance that a parallel statement may be waiting in the parallel statement queue for longer than is desired. You can prevent such scenarios by specifying the maximum time a parallel statement can wait in the parallel statement queue.
The PARALLEL_QUEUE_TIMEOUT directive attribute enables you to specify the maximum time, in seconds, that a parallel statement can wait in the parallel statement queue before it is timed out. The PARALLEL_QUEUE_TIMEOUT attribute can be set for each consumer group.
Incorrect:
Not C: ETL_GROUP PARALLEL_TARGET_PERCENTAGE is 50%. So ETL_GROUP can only consume 32 servers.
Note:
*If you want more per-workload management, you must use the following directive attributes:
/MGMT_Pn
Management attributes control how a parallel statement is selected from the parallel statement queue for execution. You can prioritize the parallel statements of one consumer group over another by setting a higher value for the management attributes of that group.
/PARALLEL_TARGET_PERCENTAGE
/PARALLEL_QUEUE_TIMEOUT
/PARALLEL_DEGREE_LIMIT_P1
* PARALLEL_DEGREE_LIMIT_P1
Degree of Parallelism Limit
You can limit the maximum degree of parallelism for any operation within a consumer group. The degree of parallelism is the number of parallel execution servers that are associated with a single operation. Use the PARALLEL_DEGREE_LIMIT_P1 directive attribute to specify the degree of parallelism for a consumer group.
The degree of parallelism limit applies to one operation within a consumer group; it does not limit the total degree of parallelism across all operations within the consumer group. However, you can combine both the PARALLEL_DEGREE_LIMIT_P1 and the PARALLEL_TARGET_PERCENTAGE directive attributes to achieve the desired control.
* PARALLEL_TARGET_PERCENTAGE
Parallel Target Percentage
It is possible for a single consumer group to launch enough parallel statements to use all the available parallel servers. If this happens, when a high-priority parallel statement from a different consumer group is run, no parallel servers are available to allocate to this group. You can avoid such a scenario by limiting the number of parallel servers that can be used by a particular consumer group.
Use the PARALLEL_TARGET_PERCENTAGE directive attribute to specify the maximum percentage of the parallel server pool that a particular consumer group can use. The number of parallel servers used by a particular consumer group is counted as the sum of the parallel servers used by all sessions in that consumer group.
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