Oracle OCP 19c 认证1Z0-083考试(第71-80题) - #宝，输了液

Posted 2021-07-09 itsaka

 

 

Choose the best answer You want to create a duplicate database DUP_DB from your production database PROD on the same host. The PROD database uses Automatic Storage Management (ASM) for storage.

Regular backups are taken using RMAN connected to a recovery catalog. You create an auxiliary instance and want to execute the command:

RMAN> DUPLICATE TARGET DATABASE TO dup_db FROM ACTIVE DATABASE;

What is a prerequisite for the successful execution of this command

A)    RMAN must be connected to the target database instance and the auxiliary instance.

B)    A most recent backup set of the PROD database must exist. C) Flashback must be enabled for the PROD database.

D) The target database must be in MOUNT state.

Answer:A

(解析:由于是用 ACTIVEDATABASE 复制数据库,所以必须要连接目标数据库和辅助实例; 如果不是 ACTIVE DATABASE 复制方式,可以不需要连接目标数据库以及 catalog 数据库。) RMAN 通过网络(active 方式)在新节点上复制数据库 新节点要求如下:
l 数据库名同 source database

l 实例名同 source database(可以不一样)

l 数据库(控制文件,在线日志,数据文件)目录:同 source database,可以不一样,

在初 始化参数文件中指定数据文件的转换。

l 目标数据库和复制数据库的密码文件的密码必须一样 l 连接到目标数据库和辅助数据库,必
 
须要用 sys 用户连接,不能用 target /方式连接,

且源数据库和目标数据库的 tnsnames 文件中包含各自的连接别名(如果使用备份进行 复制, 比如使用 SECTION SIZE 参数进行复制)

31、A container database called CDB1 is OMF-enabled. PDB_FILE_NAME_CONVERT is not configured in CDB1. PDB1 was unplugged from CDB1 earlier in the week.
Examine this command, which will be executed in CDB1:

CREATE PLUGGABLE DATABASE pdb1

USING    ‘/u01/app/oracle/oradata/pdb1.xml’    SOURCE_FILE_NAME_CONVERT    = (‘/u01/app/oracle/oradata/’, ‘/u02/app/oracle/oradata/’);
Which two are true? (Choose two.)

A.    PDB1 data files already exist in the correct location.

B.    DBMS_PDB.CHECK_PLUG_COMPATIBILITY must be run in CDB1 before executing the command.
C.    PDB_FILE_NAME_CONVERT must be set before executing the command.

D.    /u01/app/oracle/oradata/pdb1.xml does not contain the current locations of data files for PDB1. E. PDB1 must be dropped from CDB1.
Answer: AE(40 道)

(解析:目标数据文件必须存在,因为从原来拔出的 pdb 再插回去,所以先要 drop 掉,答 案 B 如果是插入到另外一个 cdb 是必须要的,但是现在不需要,因为是插入回原来的数据 库。)

32 、 Which three are true about transporting databases across platforms using Recovery Manager (RMAN) image copies? (Choose three.)
A.    By default, the transported database will use Oracle Managed Files (OMF)

B.    Data files can be converted on the destination system.

C.    Data files can be converted on the source system.

D.    A new DBID is automatically created for the transported database.

E.    Databases can be transported between systems with different endian formats. F. The password file is automatically converted by RMAN.
Answer: ABC (第 8 道)
 
33、Examine this command:

$ rhpctl move database –sourcehome Oracle_home_path –destinationhome Oracle_home_path For which two purposes can you use this command? (Choose two.)

A.    to switch an existing Oracle Database home to a newer release of Oracle software on the same server

B.    to switch to a read-only Oracle home

C.    to switch back to the previous Oracle home as part of a rollback operation

D.    to switch the Oracle Database home when using a centralized Rapid Home Provisioning server
E.    to switch to a patched Oracle Database home Answer: CE
(解析:rhpctl 功能很强大,但是该命令考的是 move database,它应用在小版本升级后,切 换新的ORACLE_HOME 目录。
RapidHomeProvisioning(RHP) 代表了一种标准的方法,以统一的方式,在软件基础设施的所 有体系结构层 (Oracle Database 和其他第三方定制软件) 上进行部署、补丁、升级、迁移等 工作,尤其是 Oracle 集群、数据库的部署、升级、补丁、迁移,以及集群节点的伸缩等操作 非常便捷。
RHP 的特点和功能 :

RHP 提供集中的软件部署和维护。软件只需要安装一次,然后存储在 RHP 服务器上,并且从那里可以随时向数据中心的任何节点或集群供应。 主要特征包括:管理现有部署,不需要任何更改、不需要重新配置、也不需要代理或守护程 序。

主要优势有:

流程自动化,减少人工参与的步骤

简化了数据库相关的安装部署、修补和升级

最大限度地减少维护的影响和风险支持大规模部署
RHP 的基本功能 :

Gold Images 集中存储,包括 GI、DB、应用、中间件等 支持安装和配置新的集群和数据库

最小化维护窗口

一条命令就能搞定安装、补丁或升级 内置了还原和从失败点继续的能力执行支持 自定义工作流
提供审计日志 支持所有部署模型——物理机器、虚拟化、容器、Oracle 多租户
 
案例:

1、

18c 在本地模式下通过 rhpctl move 切换 ORACLE HOME

注意:move 只适合于大版本相同,小版本不同的情况。比如这里是介绍从 Oracle 18.2 切换 到
18.3。

2、安装 18.3 ORACLE HOME
18.3 ORACLE_HOME 的安装(略)

3、

注意:这里是本地模式,就不能通过 rhpctl add workingcopy 来部署 183 的 ORACLE HOME 了 执
行 rhpctl move database

一条命令搞定,在 18.2 下执行 rhpctl move database

[oracle@sdb09] /home/oracle> rhpctl move database -dbname cdb2 \\

>    -sourcehome /u01/app/oracle/product/18.0.0/dbhome_1 \\

>    -desthome /u01/app/oracle/product/18.0.0/dbhome_3 \\

>    -stopoption IMMEDIATE 
34、Which two are true about changing the LOCAL_UNDO_ENABLED property to false in a CDB? (Choose two.)

A.    After the change, only a common user with the required privilege can create an undo tablespace in CDB&ROOT.

B.    Any new PDB and existing PDBs are automatically configured to use the default undo tablespace in CDB$ROOT.

C.    After the change, only one undo tablespace can exist in CDB$ROOT.

D.    After the change, any user with the required privilege can create an undo tablespace in the PDBs. E. Undo tablespaces existing in PDBs must be dropped before the change.

F. After the change, each existing PDB has to be reopened for the new undo mode to take effect.
Answer: AB

(解析:由于是在升级模式下转换模式,所以转换后就会自动使用 root 容器的 undo 表空间。跟
单个数据库一样,可以有多个 undo 表空间,但是同一时间只能用一个。) 1 、 local undo 转 shared undo 的步骤: SHUTDOWN IMMEDIATE;
 
STARTUP UPGRADE;

ALTER DATABASE LOCAL UNDO OFF; SHUTDOWN IMMEDIATE; STARTUP;
在转换完成之后,之前存在的 undo 表空间不会自动删除。如果碍事,需要进入每个 PDB 里进行 手动删除。

alter session set container=pdblhr1; DROP TABLESPACE undotbs1;
1 、 shared undo 转 local undo 的步骤: SHUTDOWN IMMEDIATE; STARTUP UPGRADE;
ALTER DATABASE LOCAL UNDO ON ; SHUTDOWN IMMEDIATE;

STARTUP;

Oracle 自动为 每个 PDB 创建了一个 undo 表空间 。在切换为本地 Undo 模式后,新创 建的数据库也是运行在本地 undo 模式上。

35、Which two are true about SQL Performance Analyzer (SPA)? (Choose two.)

A.    It is integrated with the SQL Access Advisor.

B.    It predicts the impact of system changes on SQL workload response time.

C.    It provides before and after execution statistics for each SQL statement in the analysis task D. It offers fine-grained analysis of all the SQL statements in the analysis task as a group.

E. SQL statements that were originally run concurrently are run concurrently by SPA. Answer: BC

36、A user complains about poor database performance.

You want to verify if the user’s session has waited for certain types of I/O activity. Which view displays all waits waited on by a session at least once?
A.    V$SESSION_EVENT

B.    V$SESSTAT

C.    V$SESSION_WAIT

D.    V$SESSION_WAIT_CLASS

E.    V$SESSION
 
Answer: A  (第 7 道)

(解析:这道题考的比较细,好弄清楚各个视图的包含内容。)

SQL> select distinct WAIT_CLASS,TOTAL_WAITS from V$SESSION_WAIT_CLASS; WAIT_CLASS
        User I/O 347 Administrative 3
Concurrency 5 Network 125 System I/O 15 Other 534 Idle 2795

Reference: https://docs.oracle.com/cd/E29597_01/server.1111/e16638/instance_tune.htm TOTAL_WAITS

37、Which two are true about gathering optimizer statistics? (Choose two.)

A.    Executing DBMS_STATS.GATHER_DATABASE_STATS while connected to CDB$ROOT gathers object statistics in all open PDBs except PDB$SEED.

B.    Executing DBMS_STATS.GATHER_DATABASE_STATS while connected to a PDB opened in read/write mode gathers object statistics for that PDB.

C.    Executing DBMS_STATS.GATHER_DATABASE_STATS while connected to CDB$ROOT gathers object statistics only in CDB$ROOT.

D.    System statistics can be gathered only while connected to CDB$ROOT.

E.    Executing DBMS_STATS.GATHER_DATABASE_STATS while connected to CDB$ROOT gathers object statistics in all open pluggable databases (PDBs)

Answer: BC

(解析:经过实验,AE 是错的。B 答案在统计后,会更新数据字典中统计信息。) 
38、Examine this output:

Which two are true? (Choose two.)

A.    Any PDB not specified in the plan will be unable to execute statements in parallel.

B.    PDB3 can use all available parallel execution processes at times.

C.    PDB1 is always limited to 40% of the available system resources regardless of demand.

D.    Any PDB not specified in the plan will be able to use a maximum of 16.5% of the available system resources.

E.    PDB3 is guaranteed to receive at least 20% of the available system resources if there is enough demand.
 
F.    PDB2 is guaranteed at least 25% of the available parallel execution processes if there is enough demand.

Answer: BF

股份总数为七股(三股加三股加一股)。

salespdb 和 ServicesDBPDB 各自保证有 3/7 的资源,而 hrpdb PDB 则保证有 1/7 的资源。但 是,如果没有资源争用,任何 PDB 都可以使用超过保证数量的资源。所有答案 c 错误。

39 、 Which two statements are true about Resource Manager plans for individual pluggable databases (PDB plans) in a multitenant container database (CDB)?

A.    If no PDB plan is enabled for a pluggable database, then all sessions for that PDB are treated to an equal degree of the resource share of that PDB.

B.    In a PDB plan, subplans may be used with up to eight consumer groups.

C.    If a PDB plan is enabled for a pluggable database, then resources are allocated to consumer groups across all PDBs in the CDB.

D.    If no PDB plan is enabled for a pluggable database, then the PDB share in the CDB plan is dynamically calculated.

E.    If a PDB plan is enabled for a pluggable database, then resources are allocated to consumer groups based on the shares provided to the PDB in the CDB plan and the shares provided to the consumer groups in the PDB plan.

Answer: A,E

40 、 Which two are true about the execution of operating system scripts starting from Oracle Database 19c?

(Choose two.)

A.    orainstRoot.sh can be executed automatically by the Database installer by using sudo or root credentials.

B.    root.sh can be executed automatically by the Database Installer only if it is provided with root credentials.

C.    The sudo password can be specified in a response file.

D.    root.sh can be executed automatically by the Database installer only by using sudo credentials.
E.    The sudo password must be specified in a response file.

F.    The root password cannot be specified in a response file.

Answer: AF
 
(解析:这两个脚本需要用 root 用户执行。)