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43-113

原创 Linux操作系统 作者:jbymy2000 时间:2012-03-08 09:47:34 0 删除 编辑
113. In your production database, you have multiple resource plan dir
ectives that refer to the customer group DB_GRP. Which two statements
are correct? (Choose two)
A. The parallel degree limit for DB_GRP will be the minimum of all th
e incoming values.
B. The parallel degree limit for DB_GRP will be the maximum of all th
e incoming values.
C. The maximum estimated execution time for DB_GRP would be the most
nonrestrictive of all incoming values.
D. If a session switched from the DB_GRP consumer group to another co
nsumer group because it exceeded the prescribed switch time, then tha
t session would not execute if the active session pool for the new co
nsumer group was full.
E. Is a session switched from the DB_GRP consumer group to another co
nsumer group because it exceeded the prescribed switch time, then tha
t session would execute even if the active session pool for the new c
onsumer group was full.
Answer: A,E
PARALLEL_DEGREE_LIMIT_MTH 限制任何操作的最大并行度。只能为资源使用者组,而
不能为子计划指定此方法。ABSOLUTE 方法是可能值,该方法指定可以为一个操作分配的进
程数量。如果有多个计划指令引用了相同的子计划或使用者组,则使用所有可能值中的最小
值作为该子计划或使用者组的并行度限制。
Using the active session pool feature, you can control the maximum number of
concurrently,active sessions per resource consumer group. With this functionality, a DBA can
indirectly control the amount of resources that any resource consumer group uses because
resource consumption is proportional to the number of active sessions. Using an active session
pool can help to reduce the number of servers taking resources in the system, thus avoiding
inefficient paging, swapping, and other resource depletion (such as memory) resulting from
attempting to run too many jobs simultaneously. After the active session pool is filled with active
sessions, the Resource Manager queues all subsequent sessions attempting to become active until
other active sessions complete or become inactive. An active session is one currently involved in a
transaction, query, or parallel operation. Individual parallel slaves are not counted as sessions; the
entire parallel operation counts as one active session.There is only one queue per resource
consumer group and the queuing method is first in, first out (FIFO) with a timeout. The queue is
implemented as a memory structure and cannot be queried directly.
质疑,我的疑问是E, 每一个Group 都有自己的queue,而当一个queue 满的
时候,根据FIFO,后加入的应该等待才对啊?可是为什么会是E 呢?

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