【云贝教育】Oracle 19c OCP 083题库解析(35)

作者：云贝教育郭一军

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发布时间：2024-01-11 09:19

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考试科目：1Z0-083
考试题量：85
通过分数：57%
考试时间：150min
本文为云贝教育郭一军（微信：guoyJoe）原创，请尊重知识产权，转发请注明出处，不接受任何抄袭、演绎和未经注明出处的转载。

35 、Which three are true about using Database Resource Manager in an Oracle multitenant environment?
A) A PDB-level resource plan can limit session PGA memory
B) A CDB-level resource plan is mandatory when using Pdb-level resource plans
C) A CDB-level resource plan can limit session CPU utilization.
D) A CDB-level resource plan can limit PDB UNDO use
E) PDB-level resource plans can limit uncommitted UNDO per consumer group
F) A CDB-level resource plan can limit PDB CPU utilization.

参考答案:ABF

解析：

关于在Oracle多租户环境中使用数据库资源管理器，哪三个是正确的?

A) 对， PDB级资源计划可以限制会话PGA内存

B) 对，当使用PDB级资源计划时，必须使用CDB级资源计划

C) 错，CDB级别的资源计划可以限制会话CPU利用率。（#是用share设百分比，不是session）

D) 错，CDB级别的资源计划可以限制PDB UNDO的使用 (#限制CPU,IO,MEMORY)

E) 错，PDB级资源计划可以限制每个消费组未提交的UNDO (#限制CPU,IO,MEMORY,)

F) 对， CDB级的资源计划可以限制PDB的CPU利用率。

####Session PGA Limit

For security purposes:
Avoid excessive usage of PGA memory
Set the PGA limit that a session can use before it hits an error
#####Managing Resources Between PDBs
PDBs compete for resources: CPU, Exadata I/O, and parallel servers
System shares are used to allocate resources for each PDB.
Limits are used to cap resource utilization of each PDB.
When a new PDB is plugged in, the CDB DBA can specify a default or an explicit allocation.
Each PDB has one share.
With a total of 3 shares, each PDB is guaranteed 1/3 or 33% of the CPU.
###CDB Resource Plan Basics: Limits
Four limits can be defined for each PDB:
Utilization limit for CPU, Exadata I/Os, and parallel servers
Parallel server limit to override the utilization limit
Memory_min
Memory_limit