Oracle Oracle Certifications 1Z0-062 Questions & Answers

• Question 351:

  Which two statements are true about variable extent size support for large ASM files? (Choose two.)

  A. The metadata used to track extents in SGA is reduced.

  B. Rebalance operations are completed faster than with a fixed extent size

  C. An ASM Instance automatically allocates an appropriate extent size.

  D. Resync operations are completed faster when a disk comes online after being taken offline.

  E. Performance improves in a stretch cluster configuration by reading from a local copy of an extent.

  Correct Answer: AC

  A: Variable size extents enable support for larger ASM datafiles, reduce SGA memory requirements for very large databases (A), and improve performance for file create and open operations.

  C: You don't have to worry about the sizes; the ASM instance automatically allocates the appropriate extent size.

  Note:

  *

  The contents of ASM files are stored in a disk group as a set, or collection, of data extents that are stored

  on individual disks within disk groups. Each extent resides on an individual disk. Extents consist of one or

  more allocation units (AU).

  To accommodate increasingly larger files, ASM uses variable size extents.

  *

  The size of the extent map that defines a file can be smaller by a factor of 8 and 64 depending on the file

  size. The initial extent size is equal to the allocation unit size and it increases by a factor of 8 and 64 at

  predefined thresholds. This feature is automatic for newly created and resized datafiles when the disk

  group compatibility attributes are set to Oracle Release 11 or higher.

• Question 352:

  Examine the parameter for your database instance: You generated the execution plan for the following query in the plan table and noticed that the nested loop join was done. After actual execution of the query, you notice that the hash join was done in the execution plan:

  

  

  Identify the reason why the optimizer chose different execution plans.

  A. The optimizer used a dynamic plan for the query.

  B. The optimizer chose different plans because automatic dynamic sampling was enabled.

  C. The optimizer used re-optimization cardinality feedback for the query.

  D. The optimizer chose different plan because extended statistics were created for the columns used.

  Correct Answer: A

• Question 353:

  Which three statements are true about adaptive SQL plan management? (Choose three.)

  A. It automatically performs verification or evolves non-accepted plans, in COMPREHENSIVE mode when they perform better than existing accepted plans.

  B. The optimizer always uses the fixed plan, if the fixed plan exists in the plan baseline.

  C. It adds new, bettor plans automatically as fixed plans to the baseline.

  D. The non-accepted plans are automatically accepted and become usable by the optimizer if they perform better than the existing accepted plans.

  E. The non-accepted plans in a SQL plan baseline are automatically evolved, in COMPREHENSIVE mode, during the nightly maintenance window and a persistent verification report is generated.

  Correct Answer: ADE

  With adaptive SQL plan management, DBAs no longer have to manually run the verification or evolve process for non-accepted plans. When automatic SQL tuning is in COMPREHENSIVE mode, it runs a verification or evolve process for all SQL statements that have non-accepted plans during the nightly maintenance window. If the non-accepted plan performs better than the existing accepted plan (or plans) in the SQL plan baseline, then the plan is automatically accepted and becomes usable by the optimizer. After the verification is complete, a persistent report is generated detailing how the non-accepted plan performs compared to the accepted plan performance. Because the evolve process is now an AUTOTASK, DBAs can also schedule their own evolve job at end time.

  Note:

  *

  The optimizer is able to adapt plans on the fly by predetermining multiple subplans for portions of the plan.

  *

  Adaptive plans, introduced in Oracle Database 12c, enable the optimizer to defer the final plan decision for a statement until execution time. The optimizer instruments its chosen plan (the default plan) with statistics collectors so that it can detect at runtime, if its cardinality estimates differ greatly from the actual number of rows seen by the operations in the plan. If there is a significant difference, then the plan or a portion of it will be automatically adapted to avoid suboptimal performance on the first execution of a SQL statement.

• Question 354:

  Examine the following query output:

  

  You issue the following command to import tables into the hr schema:

  $ > impdp hr/hr directory = dumpdir dumpfile = hr_new.dmp schemas=hr TRANSFORM=DISABLE_ARCHIVE_LOGGING: Y Which statement is true?

  A. All database operations performed by the impdp command are logged.

  B. Only CREATE INDEX and CREATE TABLE statements generated by the import are logged.

  C. Only CREATE TABLE and ALTER TABLE statements generated by the import are logged.

  D. None of the operations against the master table used by Oracle Data Pump to coordinate its activities are logged.

  Correct Answer: C

  Oracle Data Pump disable redo logging when loading data into tables and when creating indexes.

  The new TRANSFORM option introduced in data pumps import provides the flexibility to turn off the redo

  generation for the objects during the course of import. The Master Table is used to track the detailed

  progress information of a Data Pump job.

  The Master Table is created in the schema of the current user running the Pump Dump export or import,

  and it keeps tracks of lots of detailed information.

• Question 355:

  You notice a performance change in your production Oracle database and you want to know which change

  has made this performance difference.

  You generate the Compare Period Automatic Database Diagnostic Monitor (ADDM) report to further

  investigation.

  Which three findings would you get from the report? (Choose three.)

  A. It detects any configuration change that caused a performance difference in both time periods.

  B. It identifies any workload change that caused a performance difference in both time periods.

  C. It detects the top wait events causing performance degradation.

  D. It shows the resource usage for CPU, memory, and I/O in both time periods.

  E. It shows the difference in the size of memory pools in both time periods.

  F. It gives information about statistics collection in both time periods.

  Correct Answer: ABD

  Keyword: shows the difference.

  *

  Full ADDM analysis across two AWR snapshot periods Detects causes, measure effects, then correlates them Causes: workload changes, configuration changes Effects: regressed SQL, reach resource limits (CPU, I/O, memory, interconnect) Makes actionable recommendations along with quantified impact

  *

  Identify what changed / Configuration changes, workload changes

  *

  Performance degradation of the database occurs when your database was performing optimally in the past, such as 6 months ago, but has gradually degraded to a point where it becomes noticeable to the users. The Automatic Workload Repository (AWR) Compare Periods report enables you to compare database performance between two periods of time.

  While an AWR report shows AWR data between two snapshots (or two points in time), the AWR Compare Periods report shows the difference (ABE) between two periods (or two AWR reports with a total of four snapshots). Using the AWR Compare Periods report helps you to identify detailed performance attributes and configuration settings that differ between two time periods.

• Question 356:

  Your database supports an online transaction processing (OLTP) application. The application is undergoing some major schema changes, such as addition of new indexes and materialized views. You want to check the impact of these changes on workload performance.

  What should you use to achieve this?

  A. Database replay

  B. SQL Tuning Advisor

  C. SQL Access Advisor

  D. SQL Performance Analyzer

  E. Automatic Workload Repository compare reports

  Correct Answer: D

  You can use the SQL Performance Analyzer to analyze the SQL performance impact of any type of system change. Examples of common system changes include: ?Database upgrades ?Configuration changes to the operating system, hardware, or database ?Database initialization parameter changes ?Schema changes, such as adding new indexes or materialized views ?Gathering optimizer statistics ?SQL tuning actions, such as creating SQL profiles

  http://docs.oracle.com/cd/B28359_01/server.111/b28318/intro.htm#CNCPT961

• Question 357:

  An administrator account is granted the CREATE SESSION and SET CONTAINER system privileges.

  A multitenant container database (CDB) instant has the following parameter set:

  THREADED_EXECUTION = FALSE

  Which four statements are true about this administrator establishing connections to root in a CDB that has been opened in read only mode? (Choose four.)

  A. You can connect as a common user by using the connect statement.

  B. You can connect as a local user by using the connect statement.

  C. You can connect by using easy connect.

  D. You can connect by using OS authentication.

  E. You can connect by using a Net Service name.

  F. You can connect as a local user by using the SET CONTAINER statement.

  Correct Answer: ACDE

• Question 358:

  You are planning the creation of a new multitenant container database (CDB) and want to store the ROOT

  and SEED container data files in separate directories.

  You plan to create the database using SQL statements.

  Which three techniques can you use to achieve this? (Choose three.)

  A. Use Oracle Managed Files (OMF).

  B. Specify the SEED FILE_NAME_CONVERT clause.

  C. Specify the PDB_FILE_NAME_CONVERT initialization parameter.

  D. Specify the DB_FILE_NAMECONVERT initialization parameter.

  E. Specify all files in the CREATE DATABASE statement without using Oracle managed Files (OMF).

  Correct Answer: ABC

  You must specify the names and locations of the seed's files in one of the following ways:

  *

  (A) Oracle Managed Files

  *

  (B) The SEED FILE_NAME_CONVERT Clause

  *

  (C) The PDB_FILE_NAME_CONVERT Initialization Parameter

• Question 359:

  You are about to plug a multi-terabyte non-CDB into an existing multitenant container database (CDB).

  The characteristics of the non-CDB are as follows: Version: Oracle Database 11g Release 2 (11.2.0.2.0) 64-bit Character set: AL32UTF8 National character set: AL16UTF16 O/S: Oracle Linux 6 64-bit

  The characteristics of the CDB are as follows: Version: Oracle Database 12c Release 1 64-bit Character Set: AL32UTF8 National character set: AL16UTF16 O/S: Oracle Linux 6 64-bit

  Which technique should you use to minimize down time while plugging this non-CDB into the CDB?

  A. Transportable database

  B. Transportable tablespace

  C. Data Pump full export/import

  D. The DBMS_PDB package

  E. RMAN

  Correct Answer: B

  * Overview, example:

  -Log into ncdb12c as sys

  -Get the database in a consistent state by shutting it down cleanly.

  -Open the database in read only mode

  -Run DBMS_PDB.DESCRIBE to create an XML file describing the database.

  -Shut down ncdb12c

  -Connect to target CDB (CDB2)

  -Check whether non-cdb (NCDB12c) can be plugged into CDB(CDB2)

  -Plug-in Non-CDB (NCDB12c) as PDB(NCDB12c) into target CDB(CDB2).

  -Access the PDB and run the noncdb_to_pdb.sql script.

  -Open the new PDB in read/write mode.

  *

  You can easily plug an Oracle Database 12c non-CDB into a CDB. Just create a PDB manifest file for the non-CDB, and then use the manifest file to create a cloned PDB in the CDB.

  *

  Note that to plug in a non-CDB database into a CDB, the non-CDB database needs to be of version 12c as well. So existing 11g databases will need to be upgraded to 12c before they can be part of a 12c CDB.

• Question 360:

  You conned using SQL Plus to the root container of a multitenant container database (CDB) with SYSDBA privilege.

  The CDB has several pluggable databases (PDBs) open in the read/write mode.

  There are ongoing transactions in both the CDB and PDBs.

  What happens alter issuing the SHUTDOWN TRANSACTIONAL statement?

  A. The shutdown proceeds immediately. The shutdown proceeds as soon as all transactions in the PDBs are either committed or rolled hack.

  B. The shutdown proceeds as soon as all transactions in the CDB are either committed or rolled back.

  C. The shutdown proceeds as soon as all transactions in both the CDB and PDBs are either committed or rolled back.

  D. The statement results in an error because there are open PDBs.

  Correct Answer: B

  * SHUTDOWN [ABORT | IMMEDIATE | NORMAL | TRANSACTIONAL [LOCAL]]

  Shuts down a currently running Oracle Database instance, optionally closing and dismounting a database. If the current database is a pluggable database, only the pluggable database is closed. The consolidated instance continues to run.

  Shutdown commands that wait for current calls to complete or users to disconnect such as SHUTDOWN NORMAL and SHUTDOWN TRANSACTIONAL have a time limit that the SHUTDOWN command will wait. If all events blocking the shutdown have not occurred within the time limit, the shutdown command cancels with the following message:

  ORA-01013: user requested cancel of current operation

  * If logged into a CDB, shutdown closes the CDB instance.

  To shutdown a CDB or non CDB, you must be connected to the CDB or non CDB instance that you want

  to close, and then enter

  SHUTDOWN

  Database closed.

  Database dismounted.

  Oracle instance shut down.

  To shutdown a PDB, you must log into the PDB to issue the SHUTDOWN command.

  SHUTDOWN

  Pluggable Database closed.

  Note:

  * Prerequisites for PDB Shutdown

  When the current container is a pluggable database (PDB), the SHUTDOWN command can only be used

  if:

  The current user has SYSDBA, SYSOPER, SYSBACKUP, or SYSDG system privilege.

  The privilege is either commonly granted or locally granted in the PDB.

  The current user exercises the privilege using AS SYSDBA, AS SYSOPER, AS SYSBACKUP, or AS

  SYSDG at connect time.

  To close a PDB, the PDB must be open.