Oracle Oracle Certifications 1Z0-083 Questions & Answers

• Question 241:

  Which two are true about the Oracle dataabse methodology? (Choose two.)

  A. The Oracle Database time model should be used to find the database and instance areas most in need of tuning.

  B. Tuning activities should stop once the user is satisfied with performance.

  C. Tuning activities should stop once agreed service levels for performance have been met.

  D. The database instance memory should always be tuned before tuning any file systems.

  E. SQL statements should always be tuned before tuning any file systems.

  F. The alert log should be used to find the database and instance areas most in need of tuning.

  Correct Answer: AC

• Question 242:

  While backing up to the Oracle Fast Recovery Area (FRA), you determined the backup is taking too long and suspect a performance bottleneck. Which three are true about diagnosing and tuning these problems? (Choose three.)

  A. If an RMAN BACKUP VALIDATE command takes roughly the same time as an actual backup, then both read and write I/O are likely bottlenecks.

  B. Setting DBWR_IO_SLAVES to a non zero value can improve backup performance when using synchronous I/O.

  C. If an RMAN BACKUP VALIDATE command takes noticeably less than an actual backup, then write I/O is a likely bottleneck.

  D. If an RMAN BACKUP VALIDATE command takes roughly the same time as an actual backup, then read I/O is a likely bottleneck.

  E. Data files with a high value in V$BACKUP_SYNC_IO.DISCRETE_BYTES_PER_SECOND are a potential performance bottleneck when synchronous I/O is used.

  F. Setting DBWR_IO_SLAVES to a non zero value can improve backup performance when using asynchronous I/O/

  G. Data files with a high value in V$BACKUP_ASYNC_IO.SHORT_WAITS are a potential performance bottleneck when asynchronous I/O is used.

  Correct Answer: BCD

  One reliable way to determine whether the output device or input disk I/O is the bottleneck in a given backup job is to compare the time required to run backup tasks with the time required to run BACKUP VALIDATE of the same tasks.

  BACKUP VALIDATE of a backup performs the same disk reads as a real backup but performs no I/O to an output device.

  D -> If the time for the BACKUP VALIDATE to tape is about the same as the time for a real backup to tape, then reading from disk is the likely bottleneck.

  C -> If the time for the BACKUP VALIDATE to tape is significantly less than the time for a real backup to tape, then writing to the output device is the likely bottleneck.

  B -> Some operating systems support native asynchronous I/O. If and only if your disk does not support asynchronous I/O, then set DBWR_IO_SLAVES. Any nonzero value for DBWR_IO_SLAVES causes a fixed number of disk I/O slaves to

  be used for backup and restore, which simulates asynchronous I/O.

  G -> incorrect - The simplest way to identify the bottleneck is to find the data file that has the largest ratio for LONG_WAITS divided by IO_COUNT

  Reference: https://web.stanford.edu/dept/itss/docs/oracle/10gR2/backup.102/b14191/rcmtunin003.htm

• Question 243:

  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.

  Correct Answer: ACF

  Reference: https://books.google.com.pk/books?id=pUEkAAAAQBAJandpg=PA114andlpg=PA114anddq=V$RMAN_CONFIGURATION+view+displays+only+settings+with+values+that+have+been+modifiedandsource=blandots=fhC9A7ULeXandsig=ACfU3U2cGhTjmAOpCZhvlL5R4j6ixLRAwandhl=enandsa=Xandved=2ahUKEwjJzf-WmtnoAhXT8eAKHQ9uBG8Q6AEwAHoECAwQJg#v=onepageandq=V%24RMAN_CONFIGURATION%20view% 20displays%20only%20settings%20with%20values%20that %20have%20been%20modifiedandf=false

• Question 244:

  Which three are true about Optimizer Statistics Advisor? (Choose three.)

  A. It can be run only manually.

  B. It is part of the DBMS_ADVISOR package.

  C. It can recommend changes to improve the statistics gathering process.

  D. It always analyzes all schemas in the database.

  E. It runs automatically every night by default.

  F. It is part of the DBMS_STATS package.

  Correct Answer: CEF

  Reference: https://oracle-base.com/articles/12c/optimizer-statistics-advisor-12cr2

• Question 245:

  You issued this command:

  RMAN> BACKUP RECOVERY FILES; Which two are true? (Choose two.)

  A. All Oracle recovery files not in the current FRA that have not been backed up already, are backed up.

  B. All non-Oracle files in the current FRA that have not been backed up already, are backed up.

  C. All Oracle recovery files in the current FRA that have not been backed up already, are backed up.

  D. All Oracle recovery files in the current fast recovery area (FRA) are backed up.

  E. These backups can be written to disk or SBT.

  Correct Answer: AC

• Question 246:

  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.

  Correct Answer: AC

  Datafile 24 belongs to PDB1.

  A. It can be recovered while CDB while PDB2 is opened, as it belongs to PDB1.

  C. the datafile belongs to PDB1 and CAN be recovered while CDB is opened or in mount state.

• Question 247:

  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.

  Correct Answer: BD

  "You cannot back up from tape to tape or from tape to disk: only from disk to disk or disk to tape." https://docs.oracle.com/en/database/oracle/oracle-database/19/rcmrf/BACKUP.html#GUID-73642FF2-43C5-48B2-9969-99001C52EB50

• Question 248:

  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.

  Correct Answer: AF

• Question 249:

  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.

  Correct Answer: B

• Question 250:

  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.

  Correct Answer: AC

  Starting with Oracle Database Release 19c, the management of space in the fast recovery area is simplified. Oracle Database monitors flashback logs in the fast recovery area and automatically deletes flashback logs that are beyond the retention period. When the retention target is reduced, flashback logs that are beyond the retention period are deleted immediately.

  In scenarios where a sudden workload spike causes a large number of flashback logs to be created, the workload is monitored for a few days before deleting flashback logs that are beyond the retention period. This avoids the overhead of recreating the flashback logs, if another peak workload occurs soon after.