题目：

121.Which three statements are true regarding the functioning of the Autotask Background Process (ABP)? (Choose three.)
A. It creates jobs without considering the priorities associated with them.
B. It translates tasks into jobs for execution by the scheduler.
C. It determines the list of jobs that must be created for each maintenance window.
D. It is spawned by the MMON background process at the start of the maintenance window.
E. It maintains a repository in the SYSTEM tablespace to store the history of the execution of all tasks.
 
参考答案 BCD
解析
题目意思是，关于自动任务后台进程的功能，哪三个陈述是正确的。

参考文档：

About Automated Maintenance Tasks

Automated maintenance tasks are tasks that are started automatically at regular intervals to perform maintenance operations on the database. An example is a task that gathers statistics on schema objects for the query optimizer. Automated maintenance tasks run in maintenance windows, which are predefined time intervals that are intended to occur during a period of low system load. You can customize maintenance windows based on the resource usage patterns of your database, or disable certain default windows from running. You can also create your own maintenance windows.

-- 网上的参考文档：

    ABP相当于自动任务与调度程序之间的中介，其主要作用是将自动任务转换成Autotask作业，供调度程序执行。同样重要的是，ABP还维护所有任务执行的历史记录。ABP将其专用资料档案库存储在sysaux表空间中，您可以通过DBA_AUTOTASK_TASK 查案该资料档案库。

        ABP是在启动维护窗口时，有MMON 启动的，所有实例只需要一个ABP。MMON进程将监视ABP，并在必要时重启ABP.

        ABP可以确定为每项维护任务创建的作业列表，此列表按以下优先级排序：紧急、高级、中级。在每个优先级组中，作业是按执行的首选顺序排列的。

        ABP按照以下方式创建作业：先创建所有紧急优先级的作业，然后创建高优先级的作业，最后创建所有中优先级的作业。

        ABP将作业分配到多个调度程序作业类。这些作业类将作业映射到基于优先级的使用者组。

        注意：使用Oracle DB 11g时，不存在与特定任务永久关联的作业。因此，不能使用DBMS_SCHEDULER过程来控制自动任务的行为，请改而使用DBMS_AUTO_TASK_ADMIN过程

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