Oracle OCP 19c 认证1Z0-083考试(第81-90题) - #宝，舔狗聪

Posted 2021-07-09 itsaka

 Automatic Shared Memory Management is disabled for one of your database instances. Some SQL statements perform poorly due to excessive hard parse activity, thereby degrading performance.

What would be your next step?

A.    Run the SQL Access Advisor.

B.    Run the Memory Advisor for the shared pool.

C.    Run the SQL Tunning Advisor.

D.    Run the Memory Advisor for the Program Global Area. E. Run the Memory Advisor for the System Global Area.

Answer: B

(解析:出现上述情况,可能是共享池的 SHARED_POOL_SIZE 参数设置太小,建议是执行内 存指
导来重新设置 SHARED_POOL_SIZE 参数的值。) 
42 、 Which two are true about flashback features in Oracle Database 19c and later releases? (Choose two.)

A.    Flashback logs are automatically purged when DB_FLASHBACK_RETENTION_TARGET is set lower than the time they have already been retained.

B.    Flashback logs are monitored and proactively deleted when beyond the retention period defined in DB_FLASHBACK_RETENTION_TARGET only after there is space pressure.

C.    Flashback logs are monitored and proactively deleted when beyond the retention period defined in DB_FLASHBACK_RETENTION_TARGET before there is space pressure.

D.    Flashback logs are monitored for being older than the retention period defined in DB_FLASHBACK_RETENTION_TARGET and can be deleted by an administrator written event trigger. E. Flashback logs are automatically purged whenever the value of DB_FLASHBACK_RETENTION_TARGET is changed.

Answer: AC (解析:闪回日志能够自动维护在 19c 版本。) 
43、Examine these queries and their output:

After a system crash, an instance restart and an attempted opening of the PDBs result in:
Which two are true? (Choose two.)
 
A.    Data file 24 can be recovered while PDB2 is opened.

B.    Data file 24 must be recovered while the CDB is opened.

C.    Data file 24 can be recovered while CDB$ROOT and PDB$SEED are opened.

D.    Data file 24 cannot be recovered while the CDB is opened.

E.    Data file 24 must be recovered while PDB2 is closed. Answer: AC(50 道)
(解析:CDB 在启动时不会检查 pdb 数据文件的状态,只有当启动某个 pdb 时才会检查该 pdb 下
的数据文件,本道题故意说要启动 pdb2,其实对跟数据文件 24 没有任何关系,所以 勉强选择
A。)

44、Which two are true about RMAN duplexed backup sets? (Choose two.)

A.    A duplexed backup set uses the same number of SBT channels as a non-duplexed backup set for the same number of files.

B.    A non-duplexed backup set written to disk can be duplexed to disk by backing up the backup set that is already on disk.

C.    A non-duplexed backup set written to SBT can be duplexed to tape by backing up the backup set that is already on tape.

D.    A non-duplexed backup set written to disk can be duplexed to tape by backing up the backup set that is already on disk.

E.    A non-duplexed backup set written to SBT can be duplexed to disk by backing up the backup set that is already on tape.

F.    A duplexed backup set always uses twice as many SBT channels as a non-duplexed backup set for the same number of files.

Answer: BD

(解析:这道题难度很大。通过备份磁带上已经存在的备份集,可以将写入 SBT 的非双工备 份集双工到磁带;通过备份磁盘上已经存在的备份集,可以将写入磁盘的非双工备份集双工 到磁盘;)

45、choose three Which three are true about RMAN duplexed backup sets or image copies? A) A backup set may be duplexed with both copies written to disk.
 
B)    An image copy on disk can be copied to disk.

C)    A backup set may be duplexed with both copies written to sbt.

D)    A backup set may be duplexed so that one copy is written to sbt and the other to disk. E) An image copy on disk can be copied to sbt.

F) An image copy on sbt can be copied to disk.

Answer:ABC

(解析:根据以前的题库的答案,这个答案是以前题库的变体,镜像备份不支持 sbt,所以 EF 都是
错的

46、Which two statements are true about RMAN duplexed backups?

A)    It is not supported for image copies.

B)    It is only supported for backups to tape via the media management interface.

C)    Duplex backups can be performed on either disk or media, but cannot be performed on media and disk simultaneously.

D)    Duplex backups can contain only data files and control files.

E)    For performing duplexed backups, the parallelism for the device must be set equal to the number of copies.

Answer:AC

(解析:答案 C 的意思是 Duplexbackups 能够在磁盘或者磁带上操作,但是不能同时一个 在磁盘
一个在磁带上操作。) 
47、Which three are true about RMAN persistent configuration settings, administration, and their effects?

(Choose three.)

A.    A target database’s persistent RMAN configuration settings are always stored in the target’s control file

B.    Backup older than the recovery window retention policy are always deleted automatically if the backup location has insufficient space.

C.    Backups written to the fast recovery area (FRA) that are oboslete based on the redundancy retention policy can be deleted automatically to free space.

D.    The RMAN SHOW ALL command displays only settings with nondefault values.
 
E.    A target database’s persistent RMAN configuration settings are always synchronized automatically with the RMAN catalog.

F.    The V$RMAN_CONFIGURATION view displays only settings with values that have been modified.
G.    A DBA must specify either a redundancy retention policy or a recovery window retention policy.

Answer: ACF

(解析:答案 A 是肯定的,答案 F 是新出现的,通过验证是对的,答案 G 默认时是冗余策 略 1,不能修改为 0,所以必须两者选一。)

48、choose three Which three RMAN persistent settings can be set explicitly? A) SPFILE backup duplexing

B)    controlfile autobackup formats

C)    archivelog deletion policy

D)    image copy duplexing

E)    redo log backup duplexing F) archivelog backup duplexing Answer:BCF
(解析:本题考在 rman 中设置的内容。) 
49、Which three RMAN persistent settings can be set for a database? A. backup retention policy

B.    default backup device type

C.    default section size for backups

D.    default destinations for backups

E.    multiple backup device types for a single backup Answer: ABD (解析:使用 show all 命令就可以看到所有可以配置的内容。) 
50、The persistent configuration settings for RMAN have default for all parameters. Identify four RMAN commands that produce a multi-section backup.

A.    BACKUP TABLESPACE SYSTEM SECTION SIZE 100M;

B.    BACKUP AS COPY TABLESPACE SYSTEM SECTION SIZE 100M;

C.    BACKUP ARCHIVELOG ALL SECTION SIZE 25M;

D.    BACKUP TABLESPACE "TEMP" SECTION SIZE 10M;
 
E.    BACKUP TABLESPACE "UNDO" INCLUDE CURRENT CONTROLFILE SECTION SIZE 100M; F. BACKUP SPFILE SECTION SIZE 1M;

G. BACKUP INCREMENTAL LEVEL 0 TABLESPACE SYSAUX SECTION SIZE 100M;

Answer: ABCG

(解析:E 答案错误是因为表空间名字加了引号(单引号和双引号都不行),所以语法错误; F 答案也能够执行,但是 spfile 非常小,指定它意义不大。B 答案可能 会有异议,因为是 as copy,实际上是支持的。C 答案通过验证也是可以的。)