053 问题

时间：2014-02-09 16:45:22 阅读：458 评论：0 收藏：0 [点我收藏+]

QUESTION 206
Which statements are true regarding the Query Result Cache? (Choose all that apply.)
A. It can be set at the system, session, or table level.
B. It is used only across statements in the same session.
C. It can store the results from normal as well as flashback queries.
D. It can store the results of queries based on normal, temporary, and dictionary tables.

解析

Answer: AC

Restriction:

1.dictionary and temporary table
2.sequence currval and nextval pseudo columns
3.SQL functions....
4.Non-deterministic PL/SQL functions

QUESTION 266

View the Exhibit to examine the parameters set for your database instance. You execute the following
command to perform I/O calibration after the declaration of bind variables in the session that are used in the
command:
SQL> EXECUTE dbms_resource_manager.calibrate_io( num_physical_disks=>1, - max_latency=>50, -
max_iops=>:max_iops, -max_mbps=>:max_mbps, -
actual_latency=>:actual_latency);
Which statement describes the consequence?

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A. The command produces an error.
B. The calibration process runs successfully and populates all the bind variables.
C. The calibration process runs successfully but the latency time is not computed.
D. The calibration process runs successfully but only the latency time is computed.

解析 Answer: A

DBMS_RESOURCE_MANAGER.CALIBRATE_IO

在Oracle Database 11g Release 1中引入的过程CALIBRATE_IO从Oracle内部提供了获取存储系统性能的方法。该过程的使用存在一些限制。

该过程的调用需要SYSDBA权限。
TIMED_STATISTICS参数必须设置为TRUE，这是STATISTICS_LEVEL参数设置为TYPICAL时的默认值。
数据文件必须使用异步I/O进行访问，这是使用ASM时的默认设置。
Only users with the SYSDBA privilege can run this procedure. Qualified users must also turn on timed_statistics, and ensure asynch_io is enabled for datafiles. This can be achieved by setting filesystemio_options to either ASYNCH or SETALL. One can also query the asynch_io status by means of the following SQL statement:
```
col name format a50 SELECT name, asynch_io FROM v$datafile f,v$iostat_file i
   WHERE f.file#        = i.file_no
   AND   filetype_name  = ‘Data File‘
  / 
```
Only one calibration can be run at a time. If another calibration is initiated at the same time, it will fail.
For an Oracle Real Application Clusters (RAC) database, the workload is simultaneously generated from all instances.

QUESTION 257

Which client requests to the database can be captured as a part of the workload capture? (Choose all that

apply.)

A. flashback query

B. distributed transactions

C. logging in and logging out of sessions

D. all DDL statements having bind variables

E. direct path load of data from external files

解析Workload Capture Restrictions

The following types of client requests are not captured in a workload in the current release:

Direct path load of data from external files using utilities such as SQL*Loader
Shared server requests (Oracle MTS)
Oracle Streams
Advanced Replication streams
Non-PL/SQL based Advanced Queuing (AQ)
Flashback queries
Oracle Call Interface (OCI) based object navigations
Non SQL-based object access
Distributed transactions (any distributed transactions that are captured will be replayed as local transactions)
Remote DESCRIBE and COMMIT operations

053 问题

原文：http://www.cnblogs.com/devlin/p/3541464.html

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