oracle: ocp题解与实验(8&9/205)

题目：

8. You are using Oracle Database 10g. Which statement regarding an
incomplete recovery is true?
A. You do not need to restore all the data files.
B. You do not need to open the database with the RESETLOGS operation
C. You do not need to perform a full backup after the RESETLOGS operation.
D. You do not need to recover all the data files to the same system change
number (SCN).
Answer: C

答案解释：关于incomplete recovery的，对于不完全恢复官方描述是这样的：

Incomplete Recovery

Incomplete recovery, or point-in-time recovery, uses a backup to produce a noncurrent version of the database. In other words, you do
not apply all of the redo records generated after the most recent backup. You usually perform incomplete recovery of the whole database in the following situations:

Media failure destroys some or all of the online redo logs.

A user error causes data loss, for example, a user inadvertently drops a table.

You cannot perform complete recovery because an archived redo log is missing.

You lose your current control file and must use a backup control file to open the database.

To perform incomplete media recovery,
you must restore all datafiles from backups created prior to the time to which you want to recoverand then open the database with the

RESETLOGS

option when recovery completes. The

RESETLOGS

operation
creates a new incarnation of the database—in other words, a database with a new stream of log sequence numbers starting with log
sequence 1.

根据红字描述即可知道A和B都是错的，而D选项是关于SCN的，对于题目描述的情况，恢复时数据文件的scn都必须是相同的，当然会有不同的时候，比如数据文件read only时SCN是冻结的，但这种情况和题目情况不相符的；C选项是正确的，恢复完了没说必须做一次备份，是可选的；

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题目：

Exhibit

9.View the Exhibit and examine the Resource Manager settings for
the groups at different levels.Which two effects would be the result of this setting? (Choose two.)
A. The members of LOW_GROUP would get more priority than those of OTHER_GROUPS.
B. The members of SYS_GROUP would get most of the CPU allocation at level 1.
C. The members of LOW_GROUP would get most of the CPU allocation because it has
CPU allocation at two different levels.
D. The members of LOW_GROUP would get no CPU allocation at level1 if the members
of OTHER_GROUPS are using all the CPU at level 2.
E. The members of SYS_GROUP would get no CPU allocation at level 1 if the members
of OTHER_GROUPS are using all the CPU at level 2.
Answer: A, B

题目翻译：看图检查资源管理器的设置，不同group有不同的权限设置，下面哪两个选项描述是正确的？

答案解释：这题描述的是CPU资源使用的优先级及使用的分配比重，Level级数越小优先级越高，相同Level级别百分比大的获得的资源越多。

所以读图可以知道，Low_group和sys_group优先级最高，但sys_group可拥有最多90%资源，low_group最多10%；如果Level1分配完了仍有CPU资源剩余则可把100%剩余分给other_groups；

根据选项描述可以知道A、B是正确的；