multiple resource plan…

最新推荐文章于 2017-05-02 10:55:59 发布

原创最新推荐文章于 2017-05-02 10:55:59 发布 · 397 阅读

0 ·

CC 4.0 BY-SA版权

oracle基础专栏收录该内容

326 篇文章

订阅专栏

本文针对OCP认证考试中关于资源计划指令与消费者组DB_GRP的相关题目进行了解析，重点介绍了当多个资源计划指令指向同一消费者组时，如何确定并应用各种限制条件。

ocp试题：
97. In your production database, you have multiple resource plan directives that refer to the consumer
group DB_GRP. Which two statements are correct? (Choose two.)
A.The parallel degree limit for DB_GRP will be the minimum of all the incoming values.
B.The parallel degree limit for DB_GRP will be the maximum of all the 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 consumer group because it
exceeded the prescribed switch time, then that session would not execute if the active session pool for
the new consumer group was full.
E.If a session switched from the DB_GRP consumer group to another consumer group because it
exceeded the prescribed switch time, then that session would execute even if the active session pool for
the new consumer group was full.
Answer: AE

参考：

How Resource Plan Directives Interact--多个执行命令都引用了同一个用户组

文档地址：http://docs.oracle.com/cd/B19306_01/server.102/b14231/dbrm.htm#ADMIN027

How Resource Plan Directives Interact

If there are multiple resource plan directives that refer to the same consumer group, then the following rules apply for specific cases:

The parallel degree limit for the consumer group will be the minimum of all the incoming values.
The active session pool for the consumer group will be the sum of all the incoming values and the queue timeout will be the minimum of all incoming timeout values.
If there is more than one switch group and more than one switch time, the Database Resource Manager will choose the most restrictive of all incoming values. Specifically:
- SWITCH_TIME = min (all incoming over_switch_time values)
- SWITCH_ESTIMATE = TRUE overrides SWITCH_ESTIMATE = FALSE
  Notes:
  - If both plan directives specify the same switch time, but different switch groups, then the choice as to which group to switch to is statically but arbitrarily decided by the Database Resource Manager.
  - You cannot specify both SWITCH_TIME and SWITCH_TIME_IN_CALL plan directives for a single consumer group.
If a session is switched to another consumer group because it exceeds its switch time, that session will execute even if the active session pool for the new consumer group is full.
The maximum estimated execution time will be the most restrictive of all incoming values. Specifically:

MAX_EST_EXEC_TIME = min (all incoming MAX_EST_EXEC_TIME values)