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OCP 1Z0-053 第1~30题

原创 Oracle 作者:lhrbest 时间:2014-07-10 21:42:43 0 删除 编辑

1.While deploying a new application module,the software vendor ships the application software along with appropriate SQL plan baselines for the new SQLs being introduced.Which two statements describe the consequences?(Choose two.)

A.The plan baselines can be evolved over time to produce better performance.

B.The newly generated plans are directly placed into the SQL plan baseline without being verified.

C.The new SQL statements initially run with the plans that are known to produce good performance under standard test configuration.

D.The optimizer does not generate new plans for the SQL statements for which the SQL plan baseline

has been imported.

Answer:AC

答案解析:

(Selecting SQL Plan Baselines

在SQL Plan选择阶段,SQL每一次编绎,优化器使用基于成本的方式,建立一下best-cost的执行计划,然后去匹配SQL Plan Baselines中的SQL Plan,如果找到了匹配的SQL Plan,则会使用这个执行计划,如果没有找到匹配的SQL Plan,优化器就会去SQL Plan History中去搜索成本最低的SQL Plan,如果优化器在SQL Plan History中找不到任务匹配的SQL Plan,则该SQL Plan被作为一个Non-Accept Plan被存入SQL Plan History,新的SQL Plan直到它被验证不会引起一下性能问题才会被使用。

--如何激活使用SQL Plan Baselins

SQL>alter system set OPTIMIZER_USE_SQL_PLAN_BASELINES=true;

.Evolving SQL Plan Baselines

在SQL Plan Baselines的演变阶段,Oracle评估新的Plan的性能并将性能较好的Plan存放SQL Plan Baselines中,可以使用dbms_spm package的过程EVOLVE_SQL_PLAN_BASELINE将新的SQL Plan存入已经存在的SQL Plan Baselines中,新的Plan将会作为已经Accept Plan加入到SQL Plan Baselines中。)

2.You plan to have a larger moving window size for the default system-defined moving window baseline because you want to use the adaptive threshold.

Which statement factors in this consideration while increasing the size of the moving window.?

A.The collection level for the AWR should be set to BASIC.

B.The moving window size must be less than Undo Retention.

C.The moving window size should be greater than the Automatic Workload Repository(AWR)retention period.

D.The moving window size should be equal to or less than the Automatic Workload Repository(AWR)retention period.

Answer:D

答案解析:

(移动窗口(Moving Window)基线

   Oracle 11g引入了移动窗口(Moving Window)基线的概念,用于计算阀值的度量,窗口(window)是AWR数据在保存期限内的一个视图,窗口大小与AWR默认的保留期限8天匹配,但它可以设置为这个值的子集,在增大窗口大小前,首先要增大AWR保留期限的大小。)

3.Your database is in ARCHIVELOG mode.You have two online redo log groups,each of which contains one redo member.When you attempt to start the database,you receive the following errors:

ORA-00313:open failed for members of log group 1 of thread 1

ORA-00312:online log 1 thread 1:'D:\REDO01.LOG'

You discover that the online redo log file of the current redo group is corrupted.

Which statement should you use to resolve this issue?

A.ALTER DATABASE DROP LOGFILE GROUP 1;

B.ALTER DATABASE CLEAR LOGFILE GROUP 1;

C.ALTER DATABASE CLEAR UNARCHIVED LOGFILE GROUP 1;

D.ALTER DATABASE DROP LOGFILE MEMBER'D:\REDO01.LOG';

Answer:C

(答案解析:

参考:http://docs.oracle.com/cd/E11882_01/backup.112/e10642/osadvsce.htm#BRADV90052

[oracle@rtest~]$oerr ora 313

00313,00000,"open failed for members of log group%s of thread%s"

//*Cause:The online log cannot be opened.May not be able to find file.

//*Action:See accompanying errors and make log available.

[oracle@rtest~]$oerr ora 312

00312,00000,"online log%s thread%s:'%s'"

//*Cause:This message reports the filename for details of another message.

//*Action:Other messages will accompany this message.See the

//associated messages for the appropriate action to take.

你的数据库在归档记录模式。你有两个在线重做日志组,其中每个都包含一个重做成员。当您尝试启动数据库时,您会收到以下错误:

ORA-00313:线程1日志组1成员打开失败

ORA-00312:联机日志1线程1:'D:\REDO01.LOG

你发现当前的重做组联机重做日志文件被损坏。你应该使用哪种说法来解决这个问题?

Clearing Inactive,Unarchived Redo

Clearing a not-yet-archived redo log allows it to be reused without archiving it.This action makes backups unusable if they were started before the last change in the log,unless the file was taken offline before the first change in the log.Hence,if you need the cleared log file for recovery of a backup,then you cannot recover that backup.Clearing a not-yet-archived-redo-log,prevents complete recovery from backups due to the missing log.

To clear an inactive,online redo log group that has not been archived:

If the database is shut down,then start a new instance and mount the database:

SQL>STARTUP MOUNT

Clear the log using the UNARCHIVED keyword.

For example,to clear log group 2,issue the following SQL statement:

SQL>ALTER DATABASE CLEAR UNARCHIVED LOGFILE GROUP 2;)

4.Which three components does the Scheduler use for managing tasks within the Oracle environment?

(Choose three.)

A.a job

B.a program

C.a schedule

D.a PL/SQL procedure

Answer:ABC

答案解析:

(参考:http://blog.csdn.net/rlhua/article/details/13355531

在Oracle环境调度程序为管理任务使用哪三个组件?

A.a job作业

B.a program程序

C.a schedule调度

核心组件和主要步骤

一个作业包含两个必需组件:需要执行的操作,操作的发生时间或调度。"操作"是由命令区域和作业属性中的job_type和job_action参数表示的。"时间"是在调度中表示的,调度可以基于时间或事件,或者从属于其它作业的结果。

调度程序使用以下基本组件:

?"作业"指定要执行的操作。它可以是PL/SQL过程、纯二进制可执行文件、Java应用程序或Shell脚本。可以将程序(内容)和调度(时间)指定为作业定义的一部分,

也可以改用现有的程序或调度。可以使用作业的参数来定制其运行时行为。

?"调度"指定作业的执行时间和次数。调度可以基于时间或事件。可以为作业定义调度,方法是使用一系列日期、一个事件,或两者相结合,以及表示重复间隔的附加说

明。可以单独存储作业的调度,然后对多个作业使用同一个调度。

?"程序"是有关特定可执行文件、脚本或过程的元数据集合。自动作业将执行某个任务。使用程序,无需修改作业本身即可修改作业任务或者"内容"。可以定义程序的参数,使用户可以修改任务的运行时行为。)    

5.Examine the section of the Health Check report given below:

DBMS_HM.GET_RUN_REPORT('HM_RUN_1061')

Run Name:HM_RUN_1061 Run Id:1061

Check Name:Data Block Integrity

Check Mode:REACTIVE

Status:COMPLETED

Start Time:2007-05-12 22:11:02.032292-07:00 End Time:

2007-05-12 22:11:20.835135-07:00 Error Encountered:0

Source Incident Id:7418

Number of Incidents Created:0

Which two statements are true regarding the Health Check report?(Choose two.)

A.Health Check was performed manually.

B.Health Check was performed to check the disk image block corruptions.

C.Health Check was performed to check interblock and intersegment corruption.

D.Health Check was performed to verify the integrity of database files and report failures.

E.Health Check was performed by the Health Monitor automatically in response to a critical error.

Answer:AB

答案解析:

(GET_RUN_REPORT Function

This function returns the report for the specified checker run.

Syntax

DBMS_HM.GET_RUN_REPORT(

run_name IN VARCHAR2,

type IN VARCHAR2:='TEXT',

level IN VARCHAR2:='BASIC',)

RETURN CLOB;

Parameters

Table 72-2 GET_RUN_REPORT Function Parameters)

Parameter

Description

run_name

Name of the check's run

type

Report format type.Possible values are'HTML','XML'and'TEXT'.Default report type is'TEXT'.

level

Details of report,possible value are'BASIC'and'DETAIL'.Caution:Currently only'BASIC'level is supported.

 

这道题A答案有误,应该是自动执行,根据官网:

 

6.You are working on a CATDB database that contains an Oracle Database version 11.1 catalog schema

owned by the user RCO11.The INST1 database contains an Oracle Database version 10.1 catalog

schema owned by the user RCAT10.

You want the RMAN to import metadata for database IDs 1423241 and 1423242,registered in RCAT10,

into the recovery catalog owned by RCO11.You also want to deregister them from the catalog after import.

You executed the following commands to achieve this:

RMAN>CONNECT CATALOG rco11/password@catdb

RMAN>IMPORT CATALOG rcat10/oracle@inst1 DBID=1423241,1423242;

What happens if the RCO11 catalog has scripts with the same name as that of the scripts in RCAT10

catalog?

A.The scripts in the RCO11 catalog are overwritten.

B.RMAN renames the local stored scripts in the RCO11 catalog.

C.The RMAN session in which the command is executed aborts.

D.RMAN renames the global scripts that are imported from the RCAT10 catalog.

 

Answer:D

答案解析:

(参考:http://docs.oracle.com/cd/E11882_01/backup.112/e10642/rcmcatdb.htm#BRADV89699

global scripts:可以针对在恢复目录中注册的任何数据库执行.

在import时,如果global scripts与目标方案的global scripts名称相同,则RMAN会重新命名为COPY OF script_name。

A stored script is either global or local.It is possible for global scripts,but not local scripts,to have name conflicts during import because the destination schema contains the script name.In this case,RMAN renames the global script name to COPY OF script_name.For example,RMAN renames bp_cmd to COPY OF bp_cmd.

If the renamed global script is still not unique,then RMAN renames it to COPY(2)OF script_name.If this script name also exists,then RMAN renames the script to COPY(3)OF script_name.RMAN continues the COPY(n)OF pattern until the script is uniquely named.)

7.You need to configure fine-grained access control to external network resources from within your database.You create an access control list(ACL)using the DBMS_NETWORK_ACL_ADMIN package.

Which statement is true regarding the ACL created?

A.It is a list of remote database links stored in the XML file that are available to the users of the database.

B.It is a list of users and network privileges stored in the XML file according to which a group of users can connect to one or more hosts.

C.It is a list of users and network privileges stored in the data dictionary according to which a group of users can connect to one or more hosts.

D.It is the list of the host names or the IP addresses stored in the data dictionary that can connect to your

database through PL/SQL network utility packages such as UTL_TCP.

Answer:B

答案解析:

(The DBMS_NETWORK_ACL_ADMIN package provides the interface to administer the network Access Control List(ACL).

Examples

Example1

Grant the connect and resolve privileges for hostwww.us.oracle.comto SCOTT.

BEGIN

DBMS_NETWORK_ACL_ADMIN.CREATE_ACL(acl=>'www.xml',

description=>'WWW ACL',

principal=>'SCOTT',

is_grant=>true,

privilege=>'connect');

 

DBMS_NETWORK_ACL_ADMIN.ADD_PRIVILEGE(acl=>'www.xml',

principal=>'SCOTT',

is_grant=>true,

privilege=>'resolve');

DBMS_NETWORK_ACL_ADMIN.ASSIGN_ACL(acl=>'www.xml',

host=>'www.us.oracle.com');

END;

/

COMMIT;

Example 2

Grant the resolve privilege forwww.us.oracle.comto ADAMS.Since an ACL forwww.us.oracle.comexists already,just add the privilege for ADAMS.

BEGIN

DBMS_NETWORK_ACL_ADMIN.ADD_PRIVILEGE(acl=>'www.xml',

principal=>'ADAMS',

is_grant=>true,

privilege=>'resolve');

END;

/

COMMIT;

Example 3

Assign the ACLwww.xmlto www-proxy.us.oracle.com so that SCOTT and ADAMS can access www-proxy.us.oracle.com also.

BEGIN

DBMS_NETWORK_ACL_ADMIN.ASSIGN_ACL(acl=>'www.xml',

host=>'www-proxy.us.oracle.com');

END;

/

COMMIT;)

8.Which statement is true regarding online redefinition for the migration of BasicFile LOBs to SecureFile LOBs?

A.It cannot be done in parallel.

B.It can be done at the table level or partition level.

C.It does not require additional storage because the operation is done online.

D.Local and global indexes are maintained automatically during the operation.

Answer:B

答案解析:

(迁移到SecureFiles

使用LOB接口超集,可轻松从BasicFile LOB进行迁移。迁移到SecureFiles有两种建议方法:分区交换和联机重新定义。

分区交换:

(1)需要与表中最大分区相等的额外空间

(2)可在交换期间维护索引

(3)可将工作量分散到多个较小的维护窗口

(4)要求表或分区脱机以执行交换

联机重新定义(建议做法)

(1)不要求表或分区脱机

(2)可并行进行

(3)要求额外存储空间等于整个表,并且所有LOB段均可用

(4)要求重建所有全局索引

这些解决方案通常意味着使用输入LOB列中的数据所用磁盘空间两倍的空间。但是,使用分区和按分区执行这些操作有助于降低所需的磁盘空间。

Migrating to SecureFilesThere is no automatic method for migrating a column from a BasicFile to a SecureFile LOB.Instead,you must manually convert the data using one of the following methods:

  • CREATE TABLE...AS SELECT...
  • INSERT INTO...SELECT...
  • Online table redefintion.
  • Export/Import
  • Create a new column,update the new column with the values in the original column,then drop the old column.
  • Create a new column,update the new column with the values in the original column,rename the table and create a view with the original name that only references the new column.

With the exception of the export/import method,all the options will require considerable amounts of disk space when converting LOBs containing large amounts of data.

Oracle Streams does not currently support SecureFiles,so avoid migrating LOBs that are using in conjunction with streams.)

9.Which statement describes the information returned by the DBMS_SPACE.SPACE_USAGE procedure for LOB space usage?

A.It returns space usage of only BasicFile LOB chunks.

B.It returns space usage of only SecureFile LOB chunks.

C.It returns both BasicFile and SecureFile LOB space usage for only nonpartitioned tables.

D.It returns both BasicFile and SecureFile LOB space usage for both partitioned and nonpartitioned

tables.

Answer:B

答案解析:

(SPACE_USAGE Procedures

The first form of the procedure shows the space usage of data blocks under the segment High Water Mark.You can calculate usage for LOBs,LOBPARTITIONS and LOB SUBPARTITIONS.This procedure can only be used on tablespaces that are created with auto segment space management.The bitmap blocks,segment header,and extent map blocks are not accounted for by this procedure.

The second form of the procedure returns information about SECUREFILE LOB space usage.It will return the amount of space in blocks being used by all the SECUREFILE LOBs in the LOB segment.The procedure displays the space actively used by the LOB column,freed space that has retention expired,and freed space that has retention unexpired.)

10.Consider the following scenario for your database:

-Backup optimization is enabled in RMAN.The recovery window is set to 7 days in RMAN.The most

recent backup to disk for the TOOLS tablespace was taken on November 3,2007.

The TOOLS tablespace is read-only since November 4,2007.

On November 23,2007,you issue the RMAN command to back up the database to disk.Which statement

is true regarding the backup of the TOOLS tablespace?

A.The RMAN backup fails because the TOOLS tablespace is read-only

B.The RMAN skips the backup of the tablespace because backup optimization is enabled

C.The RMAN makes backup because optimization can be enabled only for backups to disk

D.The RMAN makes the backup because no backup of the tablespace exists within the seven day

window

Answer:D

答案解析:

(参考:备份优化:http://blog.csdn.net/rlhua/article/details/12312463

备份优化是指:通过跳过未更改的文件(如已经备份的只读和脱机数据文件)优化整个数据库备份。

启用了备份优化:RMAN>CONFIGURE BACKUP OPTIMIZATION ON;

参考:指定保留策略:http://blog.csdn.net/rlhua/article/details/12308231

保留恢复到指定天数内任意时间的状态所需的备份(时间点恢复)

可以使用下列命令语法配置恢复窗口保留策略:

RMAN>CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF<天数>DAYS;

本题设置为7天。

RMAN>CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 7 DAYS;

题意:最近的一次TOOLS表空间是November 3,2007,November 4,2007变为只读,November 23,2007执行RMAN备份。

仅当符合保留策略的备份不存在时,备份优化才会让RMAN备份只读表空间。

根据备份优化,如果在November 3,2007之后的7天内备份,则在rman备份时跳过只读表空间,即TOOLS表空间。

如果超过7天,即之前保留的备份已经没有了,再次执行RMAN命令时,此时的TOOLS表空间并没有备份,则执行RMAN命令时,TOOLS表空间也要被备份。

故选D。tools这个只读表空间在7天的时间窗口没有备份。)

  1. View the Exhibit to examine the metrics with a threshold.Which statement is true regarding the Number of Transactions(per second)metric?

    A.Oracle uses statistical relevance to determine when an adaptive threshold has been breached for the metric.

    B.The statistics for the metric values observed over the baseline time period are not examined to determine threshold values.

    C.Oracle determines when an adaptive threshold has been breached based on the maximum value captured by the baseline.

    D.The total concurrent number of threshold violations,which must occur before an alert is raised for the metric,has been set to zero.

    Answer:A

    答案解析:

    (Adaptive Thresholds

    Adaptive thresholds enable you to monitor and detect performance issues while minimizing administrative overhead.Adaptive thresholds can automatically set warning and critical alert thresholds for some system metrics using statistics derived from metric values captured in the moving window baseline.The statistics for these thresholds are recomputed weekly and might result in new thresholds as system performance evolves over time.In addition to recalculating thresholds weekly,adaptive thresholds might compute different thresholds values for different times of the day or week based on periodic workload patterns.

    For example,many databases support an online transaction processing(OLTP)workload during the day and batch processing at night.The performance metric for response time per transaction can be useful for detecting degradation in OLTP performance during the day.However,a useful OLTP threshold value is almost certainly too low for batch workloads,where long-running transactions might be common.As a result,threshold values appropriate to OLTP might trigger frequent false performance alerts during batch processing.Adaptive thresholds can detect such a workload pattern and automatically set different threshold values for the daytime and nighttime.)

    12.You performed the RMAN database backup having a backupset key number 231 with the KEEP

    FOREVER option.

    After some days,you want to change the status of the database backup and you issued the following

    command:

    RMAN>CHANGE BACKUPSET 231 NOKEEP;

    What is the implication of this command?

    A.The backup is deleted.

    B.The backup is marked unavailable.

    C.The backup overrides the backup retention policy.

    D.the backup becomes eligible for deletion according to the existing retention policy

    Answer:D

    答案解析:

    (参考:http://docs.oracle.com/cd/E11882_01/backup.112/e10643/rcmsubcl011.htm#RCMRF90453

    你执行RMAN数据库备份带一个键号231的、永远保持选项的备份集。过了些日子,你要更改的数据库备份的状态,并发出以下命令:

    RMAN>CHANGE BACKUPSET 231 NOKEEP;

    D,备份变为适合根据已有的保持策略来进行删除

    NOKEEP    Specifies that any KEEP attributes no longer apply to the backup.Thus,the backup is a normal backup that is subject to the configured backup retention policy.This is the default behavior if no KEEP option is specified.)

    13.View the Exhibit that sets the threshold for the Current Open Cursors Count metric.Why is the Significance Level threshold type not available in the threshold setting?

    A.because AWR baseline is not enabled

    B.because Current Open Cursors Count is not a basic metric

    C.because the STATISTICS_LEVEL parameter is set to BASIC

    D.because the AWR baseline is a system-defined moving window baseline

    Answer:B

    答案解析:

    (Percentage of maximum thresholds are most useful when a system is sized for peak workloads,and you want to be alerted when the current workload volume is approaching or exceeding previous high values.Metrics that have an unknown but definite limiting value are good candidates for these settings.For example,the redo generated per second metric is typically a good candidate for a percentage of maximum threshold.

    Significance level thresholds are most useful for metrics that should exhibit statistically stable behavior when the system is operating normally,but might vary over a wide range when the system is performing poorly.For example,the response time per transaction metric should be stable for a well-tuned OLTP system,but may fluctuate widely when performance issues arise.Significance level thresholds are meant to generate alerts when conditions produce both unusual metric values and unusual system performance.)

    14.Which two statements are true regarding hot patching?(Choose two.)

    A.It requires relinking of the Oracle binary.

    B.It does not require database instance shutdown.

    C.It can detect conflicts between two online patches.

    D.It is available for installing all patches on all platforms.

    E.It works only in a single database instance environment.

    Answer:BC

    答案解析:

    (A regular RDBMSpatch is comprised of one or more object(.o)files and/or libraries(.afiles).Installing a regular patch requires shuttingdown the RDBMS instance,re-linking the oracle binary,and restarting theinstance;uninstalling a regular patch requires the same steps.

    On the otherhand,an online patch is a special kind of patch that can be applied to a live,running RDBMS instance.An online patch contains a single shared library;installing an online patch does not require shutting downthe instance or relinking the oracle binary.An online patch can beinstalled/un-installed using Opatch(which uses oradebug commands toinstall/uninstall the patch).)

    15.You are in the process of creating a virtual private catalog in your Oracle Database 11g database.The PROD1,PROD2,and PROD3 Oracle Database 10g databases are registered in the base recovery catalog.The database user who owns the base recovery catalog is CATOWNER.CATOWNER executes the following command to grant privileges to a new user VPC1 using Oracle Database 11g RMAN execut ables:

    RMAN>GRANT CATALOG FOR DATABASE prod1,prod2 TO vpc1;

    Then you issue the following commands:

    RMAN>CONNECT CATALOG vpc1/oracle@catdb;

    RMAN>SQL"EXEC catowner.dbms_rcvcat.create_virtual_catalog;"

    What is the outcome of the above commands?

    A.They execute and create a virtual catalog for pre-Oracle 11g clients.

    B.They produce an error because PROD1 and PROD2 databases belong to the older version.

    C.They produce an error because you need to connect as CATOWNER to execute this packaged

    procedure.

    D.They produce an error because you need to connect to the target database to execute this packaged

    procedure.

    Answer:A

    答案解析:

    (参考:http://blog.csdn.net/rlhua/article/details/13169205

    以下是使用rman虚拟专用目录步骤:

    1.创建RMAN基本目录:

    RMAN>CONNECT CATALOG catowner/oracle@catdb

    RMAN>CREATE CATALOG;

    2.将RECOVERY_CATALOG_OWNER授予给VPC所有者:

    SQL>CONNECT SYS/oracle@catdb AS SYSDBA

    SQL>GRANT RECOVERY_CATALOG_OWNER to vpcowner;

    3a.将REGISTER授予给VPC所有者:

    RMAN>CONNECT CATALOG catowner/oracle@catdb

    RMAN>GRANT REGISTER DATABASE TO vpcowner;

    3b.或将CATALOG FOR DATABASE授予给VPC所有者:

    RMAN>GRANT CATALOG FOR DATABASE db10g TO vpcowner;

    4a.为11g客户机创建虚拟目录:

    RMAN>CONNECT CATALOGvpcowner/oracle@catdb

    RMAN>CREATE VIRTUAL CATALOG;

    4b.或者为11g之前的客户机创建虚拟目录:

    SQL>CONNECT vpcowner/oracle@catdb

    SQL>exec catowner.dbms_rcvcat.create_virtual_catalog;

    5.在目录中注册新数据库:

    RMAN>CONNECT TARGET/CATALOG vpcowner/oracle@catdb

    RMAN>REGISTER DATABASE;

    6.使用虚拟目录:

    RMAN>CONNECT TARGET/CATALOG vpcowner/oracle@catdb;

    RMAN>BACKUP DATABASE;

    可以为数据库组和用户组创建虚拟专用RMAN目录。

    1.目录所有者将创建基本目录。

    2.目录数据库的DBA可以创建拥有虚拟专用目录(VPC)的用户,并授予其RECOVERY_CATALOG_OWNER权限。

    3.基本目录的所有者可为VPC所有者授予访问先前注册的数据库的权限或授予REGISTER权限。GRANT CATALOG命令如下:

    GRANT CATALOG FOR DATABASE prod1,prod2 TO vpcowner;

    GRANT REGISTER命令如下:

    GRANT REGISTER DATABASE TO vpcowner;

    然后,虚拟目录所有者可连接到特定目标的目录,或者注册一个目标数据库。配置完VPC之后,VPC所有者可像使用标准基本目录一样使用该目录。

    4.创建虚拟专用目录。

    a.如果目标数据库是Oracle Database 11g数据库并且RMAN客户机是11g客户机,则可使用RMAN命令:

    CREATE VIRTUAL CATALOG;

    b.如果目标数据库是Oracle Database 10g发行版2或更早版本(使用兼容客户机),则必须从SQL*Plus执行提供的过程:

    BASE_CATALOG_OWNER.DBMS_RCVCAT.CREATE_VIRTUAL_CATALOG;

    5.使用VPC所有者登录名连接到该目录,将其作为常规目录使用。

    6.虚拟目录所有者只能查看其有访问权限的那些数据库。对于大多数RMAN操作,你还需要针对目标数据库的SYSDBA或SYSOPER权限。)

    16.Because of a logical corruption in your production database,you wanted to perform Tablespace Point in Time Recovery(TSPITR).But before you start the recovery,you queried the

    TS_PITR_OBJECTS_TO_BE_DROPPED view and realized that there are a large number of objects that

    would be dropped when you start the recovery by using this method.You want to preserve these objects.

    Which option must you use to perform TSPITR and preserve the object?

    A.Perform Export before TSPITR and Import after TSPITR

    B.Move objects to another schema that has the same tablespace assigned

    C.Perform Incomplete Recovery before TSPITR with the Log Sequence Number(LSN)

    D.Perform Incomplete Recovery before TSPITR with the System Change Number(SCN)

    Answer:A

    答案解析:

    (参考:http://docs.oracle.com/cd/E11882_01/backup.112/e10642/rcmtspit.htm#BRADV89795

    When you perform RMAN TSPITR on a tablespace,objects created after the target recovery time are lost.You can preserve such objects after they are identified by exporting them before TSPITR with the Data Pump Export utility and reimporting them afterward with Data Pump Import.

    To determine which objects are lost in TSPITR,query the TS_PITR_OBJECTS_TO_BE_DROPPED view on the primary database.)

     

    17.The INV_HISTORY table is created using the command:

    SQL>CREATE TABLE INV_HISTORY(inv_no NUMBER(3),inv_date DATE,inv_amt NUMBER(10,2))

    partition by range(inv_date)interval(numtoyminterval(1,'month'))

    (partition p0

    values less than(to_date('01-01-2005','dd-mm-yyyy')),

    partition p1 values less than

    (to_date('01-01-2006','dd-mm-yyyy')));

    The following data has been inserted into the INV_HISTORY table:

    INV_NO INV_DATE INV_AMT 1 30-dec-2004 1000 2 30-dec-2005 2000 3 1-feb-2006 3000 4 1-mar-2006

    4000 5 1-apr-2006 5000

    You would like to store the data belonging to the year 2006 in a single partition and issue the command:

    SQL>ALTER TABLE inv_history MERGE PARTITIONS

    FOR(TO_DATE('15-feb-2006','dd-mon-yyyy')),FOR(TO_DATE('15-apr-2006'))INTO PARTITION sys_py;

    What would be the outcome of this command?

    A.It executes successfully,and the transition point is set to'1-apr-2006'.

    B.It executes successfully,and the transition point is set to'15-apr-2006'.

    C.It produces an error because the partitions specified for merging are not adjacent.

    D.It produces an error because the date values specified in the merge do not match the date values stored in the table.

    Answer:C

    答案解析;

    (A typical scenario might not only need to compress old data,but also to merge several old partitions to reflect the granularity for a later backup of several merged partitions.Let us assume that a backup(partition)granularity is on a quarterly base for any quarter,where the oldest month is more than 36 months behind the most recent month.In this case,we are therefore compressing and merging sales_01_1998,sales_02_1998,and sales_03_1998 into a new,compressed partition sales_q1_1998.

  • Create the new merged partition in parallel in another tablespace.The partition will be compressed as part of the MERGE operation:
  • ALTER TABLE sales MERGE PARTITIONS sales_01_1998,sales_02_1998,sales_03_1998 INTO PARTITION sales_q1_1998 TABLESPACE archive_q1_1998 COMPRESS UPDATE GLOBAL INDEXES PARALLEL 4;)

18.You create a new Automatic Database Diagnostic Monitor(ADDM)task:

instance_analysis_mode_task.To view the ADDM report,you use the following command:

SQL>SELECT dbms_addm.get_report('my_instance_analysis_mode_task')FROM dual;

You want to suppress ADDM output relating to Segment Advisor actions on user SCOTT's segments.

What would you do to achieve this?

A.Add a finding directive for the ADDM task.

B.Add a segment directive for the ADDM task.

C.Add a parameter directive for the ADDM task.

D.Disable the Segment Advisor from the Automatic Maintenance Task.

Answer:B

答案解析:

(了Oracle数据库10g,表空间的磁盘空间使用率由数据库主动管理。可以通过以下方法实现主动表空间管理:通过使用数据库警报,当表空间在可用磁盘空间较低的情况下运行时将向您发出通知。然后,可以为表空间提供更多磁盘空间,或从表空间回收空间。这样,便可以避免空间不足的情况。收集到的信息存储在自动负载信息库(AWR)中,并用于执行数据库增长趋势分析和容量规划。

可以根据表空间的饱和度定义表空间阈值。严重阈值和警告阈值是两个应用于表空间的阈值。DBMS_SERVER_ALERTS程序包包含用于设置和获取阈值的过程。还可以使用EM界面定义阈值。当表空间饱和度超过这两个限制中的任何一个时,将引发相应的警报。阈值按表空间大小的百分比或按字节表示。

DBMS_ADVISOR

DBMS_ADVISOR is part of the Server Manageability suite of Advisors,a set of expert systems that identifies and helps resolve performance problems relating to the various database server components.)

19.A PL/SQL procedure queries only those columns of a redefined table that were unchanged by the online table redefinition.What happens to the PL/SQL procedure after the online table redefinition?

A.It remains valid.

B.It becomes invalid for all options of online table redefinition but automatically gets revalidated the next

time it is used.

C.It becomes invalid for all options of online table redefinition and is automatically recompiled during

online redefinition of the table.

D.It becomes invalid only if the storage parameters have been modified and it automatically gets

revalidated the next time it is used.

Answer:A

答案解析:

(Oracle9i在其DBMS_REDEFINITION软件包中引入了在表在线重定义功能。有了DBMS_REDEFINITION软件包,你就可以:

1.拷贝表格(用CTAS)。

2.创建表格的快照(snapshot)。

3.把重定义表的过程中所发生的变化进行排队。

4.并用变化队列来同步重定义后的表。

这个特性对24/7Oracle数据库来说非常重要,这是由于DBA现在可以在保持表的可更新性的同时重新组织表的结构。)

  1. View the Exhibit and examine the resource consumption details for the current plan in use by the database instance.

    Which two statements are true based on the output?(Choose two.)

    Exhibit:

    A.An attempt to start a new session by the user belonging to DSS_QUERIES fails with an error

    B.A user belonging to DSS_QUERIES can log in to a new session but the session will be queued

    C.The CPU_WAIT_TIME column indicates the total time that sessions in the consumer group waited for the CPU due to resource management

    D.The CPU_WAIT_TIME column indicates the total time that sessions in the consumer group waited for the CPU due to resource management,I/O waits,and latch or enqueue contention

    Answer:BC

    答案解析:

    (参考:http://docs.oracle.com/cd/E11882_01/server.112/e40402/dynviews_2157.htm#REFRN30214

    V$RSRC_CONSUMER_GROUP:包含所有活动组统计信息的视图

    下面简要描述了此视图中的部分列:

    ?name:使用者组的名称。

    ?active_sessions:此使用者组中的当前活动会话数。

    ?execution_waiters:等待时间片断的活动会话数。

    ?requests:此使用者组中累计执行的请求数。

    QUEUE_LENGTH:Number of sessions waiting in the queue:在队列中等待的会话数。

    CPU_WAIT_TIME:Cumulative amount of time that sessions waited for CPU because of resource management.This does not include waits due to latch or enqueue contention,I/O waits,and so on.:因为资源理,会话等待CPU累积大量时间。这不包括锁存或排队争用,I/O等待等等。

    会话等待CPU的累计时间。

    ?consumed_cpu_time:所有会话累计消耗的CPU时间。)

    21.You are managing an Oracle Database 11g instance.You want to create a duplicate database for

    testing purpose.

    What are the prerequisites for performing the active database duplication?(Choose all that apply.)

    A.The source database backup must be copied over the net for test database.

    B.The source database must be run in ARCHIVELOG mode if the database is open.

    C.The source database must be shut down cleanly if the database is in mounted state.

    D.A net service name should be set up and a listener configured with the target as well as the source database.

    Answer:BCD

    答案解析:

    (参考:http://blog.csdn.net/rlhua/article/details/13509067

    官方参考:http://docs.oracle.com/cd/E11882_01/backup.112/e10643/rcmsynta020.htm#RCMRF90152

    通过使用Oracle Enterprise Manager或RMAN DUPLICATE命令的FROM ACTIVE DATABASE子句,可以指示源数据库直接将映像副本和归档日志副本复制到辅助实例。

    此操作不需要使用备份。RMAN作为TARGET连接到源数据库实例并作为AUXILIARY连接到辅助实例。

    通过实例间的网络连接将数据库文件从源数据库复制到目标数据库或辅助实例。RMAN随后使用"内存脚本"(仅包含在内存中)完成恢复并打开数据库。

    Active duplication:RMAN duplicates the files directly from either an open or mounted database.

    A,从活动数据库复制,不需要拷贝备份。错误。

    B,源数据库必须是归档模式,正确。

    C,如果数据库是mount状态,那么源数据库一定是shut down cleanly。正确。

    D,需要建立网络服务名和配置监听。正确。

    Prerequisites Specific to Active Database Duplication

    When you execute DUPLICATE with FROM ACTIVE DATABASE,at least one normal target channel and at least one AUXILIARY channel are required.

    When you connect RMAN to the source database as TARGET,you must specify a password,even if RMAN uses operating system authentication.The source database must be mounted or open.If the source database is open,then archiving must be enabled.If the source database is not open,then it must have been shut down consistently.

    When you connect RMAN to the auxiliary instance,you must provide a net service name.This requirement applies even if the auxiliary instance is on the local host.

    The source database and auxiliary instances must use the same SYSDBA password,which means that both instances must have password files.You can create the password file with a single password so you can start the auxiliary instance and enable the source database to connect to it.

    The DUPLICATE behavior for password files varies depending on whether your duplicate database acts as a standby database.If you create a duplicate database that is not a standby database,then RMAN does not copy the password file by default.You can specify the PASSWORD FILE option to indicate that RMAN should overwrite the existing password file on the auxiliary instance.If you create a standby database,then RMAN copies the password file to the standby host by default,overwriting the existing password file.In this case,the PASSWORD FILE clause is not necessary.

    You cannot use the UNTIL clause when performing active database duplication.RMAN chooses a time based on when the online data files have been completely copied,so that the data files can be recovered to a consistent point in time.)

    22.An index called ORD_CUSTNAME_IX has been created on the CUSTNAME column in the ORDERS table using the following command:

    SQL>CREATE INDEX ord_custname_ix ON orders(custname);

    The ORDERS table is frequently queried using the CUSTNAME column in the WHERE clause.You want to check the impact on the performance of the queries if the index is not available.You do not want the index to be dropped or rebuilt to perform this test.

    Which is the most efficient method of performing this task?

    A.disabling the index

    B.making the index invisible

    C.making the index unusable

    D.using the MONITORING USAGE clause for the index

    Answer:B

    答案解析:

     

    (Creating an Invisible Index

    An invisible index is an index that is ignored by the optimizer unless you explicitly set the OPTIMIZER_USE_INVISIBLE_INDEXES initialization parameter to TRUE at the session or system level.

    To create an invisible index:

    Use the CREATE INDEX statement with the INVISIBLE keyword.

    The following statement creates an invisible index named emp_ename for the ename column of the emp table:

    CREATE INDEX emp_ename ON emp(ename)

    TABLESPACE users

    STORAGE(INITIAL 20K

    NEXT 20k)INVISIBLE;

    隐藏索引

    scott@TESTDB>create index emp_ename_i on emp(ename)invisible;

    Index created.

    scott@TESTDB>select index_name,VISIBILITY from user_indexes;

    INDEX_NAME VISIBILIT

    -----------------------------

    PK_EMP VISIBLE

    EMP_SAL_F VISIBLE

    EMP_COMM_I VISIBLE

    EMP_ENAME_I INVISIBLE

    PK_DEPT VISIBLE

    scott@TESTDB>select*from emp where ename='KING';

    没有走索引

    切换到系统用户,修改参数

    sys@TESTDB>alter session set optimizer_use_invisible_indexes=true;

    Session altered.

    sys@TESTDB>select*from scott.emp where ename='KING';

    隐藏索引变正常索引或反之

    sys@TESTDB>alter index scott.emp_ename_i visible;

    Index altered.

    scott@TESTDB>select index_name,VISIBILITY from user_indexes;

    INDEX_NAME VISIBILIT

    ---------------------------------------

    PK_EMP VISIBLE

    EMP_SAL_F VISIBLE

    EMP_COMM_I VISIBLE

    EMP_ENAME_I VISIBLE

    PK_DEPT VISIBLE

    多个索引,把慢的索引隐藏点,让他走快的索引

    scott@TESTDB>alter index emp_ename_i visible;

    Index altered.

     

    scott@TESTDB>alter index emp_ename_i invisible;

    Index altered.)

     

    23.Which tasks can be accomplished using the DBMS_LOB.SETOPTIONS procedure?

    A.only encryption and compression settings for all SecureFile LOBs

    B.only encryption and deduplication settings for only SecureFile CLOBs

    C.deduplication,encryption,and compression settings for all SecureFile LOBs

    D.deduplication,encryption,and compression settings only for SecureFile CLOBs

    Answer:C

    答案解析:

    (SETOPTIONS Procedures

    This procedure enables/disables CSCE features on a per-LOB basis,overriding the default LOB column settings.

    Syntax

    DBMS_LOB.SETOPTIONS(

    lob_loc IN BLOB,

    option_types IN PLS_INTEGER,

    options IN PLS_INTEGER);

    DBMS_LOB.SETOPTIONS(

    lob_loc IN CLOB CHARACTER SET ANY_CS,

    option_types IN PLS_INTEGER,

    options IN PLS_INTEGER);

    Parameters

    Table 82-90 SETOPTIONS Procedure Parameter

    Parameter

    Description

    lob_loc

    Locator for the LOB to be examined.For more information,see Operational Notes.

    option_type

    See DBMS_LOB Constants-Option Types

    options

    See DBMS_LOB Constants-Option Values

    Exceptions

    Table 82-91 SETOPTIONS Procedure Exceptions

    Exception

    Description

    SECUREFILE_BADLOB

    Unsupported object type for the operation

    INVALID_ARGVAL

    A parameter value was invalid

    QUERY_WRITE

    Cannot perform operation during a query

    BUFFERING_ENABLED

    Cannot perform operation with LOB buffering enabled

     

    Usage Notes

  • DBMS_LOB.SETOPTIONS cannot be used to enable or disable encryption on individual LOBs.
  • You cannot turn compression or deduplication on or off for a SecureFile column that does not have those features on.The GETOPTIONS Functions and SetOptions Procedures work on individual SecureFiles.You can turn off a feature on a particular SecureFile and turn on a feature that has already been turned off by SetOptions,but you cannot turn on an option that has not been given to the SecureFile when the table was created.)

24.Which of the following information will be gathered by the SQL Test Case Builder for the problems pertaining to SQL-related problems?(Choose all that apply.)

A.ADR diagnostic files

B.all the optimizer statistics

C.initialization parameter settings

D.PL/SQL functions,procedures,and packages

E.the table and index definitions and actual data

Answer:BCE

答案解析:

   (SQL Test Case Builder

   当你向Oracle Support人员报告一个问题时,收集和重新生成问题出现的情景常常很困难。新的SQL Test Case Builder让你能容易地捕捉到有关SQL问题的信息,并上传给Oracle Support,这样Oracle Support可以重新生成问题并测试它。SQL Test Case Builder收集SQL查询的细节、对象定义、存储代码(如程序包)、初始化参数和优化程序统计数据等信息。它不收集查询使用的实际数据。

   可以用Database Control或新DBMS_SQLDIAG程序包访问SQL Test Case Builder。)

25.You enabled Flashback Data Archive on the INVENTORY table.Which DDL operation is supported on the table after enabling Flashback Data Archive?

A.Drop the table.

B.Partition the table

C.Truncate the table.

D.Add a column to the table.

E.Rename a column in the table.

Answer:D

答案解析:

(如果将表指定了闪回数据归档区,则不能对表进行如下操作。

删除,重令名,或者修改列;

进行分区或者子分区操作;

转换long到lob类型;

ALTER TABLE…UPGRADE TABLE操作;

drop、rename、trunacte表。

例如:

scott@11gR1>drop table test1;

drop table test1

*

ERROR at line 1:

ORA-55610:Invalid DDL statement on history-tracked table)

26.You are working on a CATDB database that contains an Oracle Database version 11.1 catalog schema

owned by the user RCO11.The INST1 database contains an Oracle Database version 10.1 catalog

schema owned by the user RCAT10.

You want the RMAN to import metadata for database IDs 1423241 and 1423242,registered in RCAT10,

into the recovery catalog owned by RCO11.You executed the following commands:

RMAN>CONNECT CATALOG rco11/password@catdb

RMAN>IMPORT CATALOG rcat10/oracle@inst1 NO UNREGISTER;

Which two statements are true regarding the tasks accomplished with these commands?(Choose two.)

A.They import all metadata from the RCAT10 catalog.

B.They unregister the database from the RCAT10 catalog.

C.They do not register the databases registered in the RCAT10 catalog.

D.They register all databases registered in the RCAT10 catalog.

Answer:AD

答案解析:

(参考:http://blog.csdn.net/rlhua/article/details/13169205

使用IMPORT CATALOG命令可将元数据从一个恢复目录方案导入至其它目录方案中。如果创建了不同版本的目录方案来存储多个目标数据库的元数据,则使用此命令可以为所有数据库维护单个目录方案。

IMPORT CATALOG

[DBID=[,,…]]

[DB_NAME=[,

[NO UNREGISTER];

是源恢复目录连接字符串。源恢复目录方案的版本必须等于RMAN可执行文件的当前版本。如果需要,将源目录升级到当前RMAN本版。

DBID:你可以指定数据库ID的列表,数据库ID的元数据应从源目录方案导入。未指定列表时,RMAN将所有数据库ID的元数据从源目录方案合并到目标目录方案中。如果已在恢复目录方案中注册了合并元数据的数据库,RMAN就会发出错误消息。

DB_NAME:可以指定应导入其元数据的数据库的名称列表。如果数据库名称不明确,RMAN就会发出错误消息。

NO UNREGISTER:默认情况下,导入的数据库ID在成功导入后从源恢复目录方案中注销。使用NO UNREGISTER选项,可以强制RMAN将导入的数据库ID保留在源目录方案中。

RMAN>CONNECT CATALOG rco11/password@catdb

RMAN>IMPORT CATALOG rcat10/oracle@inst1 NO UNREGISTER;

RMAN将数据库inst1的元数据导入到catdb数据库中的rco11方案。而NO UNREGISTER说明,在rcat10方案中注册的数据库将不会注销,继续注册在rcat10用户目录中。)

27.You are using the flash recovery area(fast recovery area in 11g Release 2)to store backup related files in your database.

After regular monitoring of space usage in the Mash recovery area.You realize that the flash recovery area is(jetting filled up very fast and it is running out of space.Your database flash recovery area is low on specie and you have no more room on disk.Proactively,which two options could you use to make more space available in the flash recovery[Choose two]

A.Change the RMAN archived log deletion policy.

B.Use the RMAN CROSSCHECK command to reclaim the archived log space.

C.Change the RMAN retention policy to retain backups for a shorter period of time.

D.Use OS command to move files from the flash recovery area to some other location

Answer:BD

答案解析:

(您正在使用闪回恢复区(11g第2版中的快速恢复区)在你的数据库中存储与备份相关的文件。在定期监测在糊状恢复区的空间使用情况之后。你会意识到,闪回恢复区被喷射似地非常快地填充起来且运行空间不足,你的数据库闪回恢复区空间不足,你没有更多的空间在磁盘上。

你可以主动使用哪两个选项以在闪回恢复区上腾出更多可用空间

B.Use the RMAN CROSSCHECK command to reclaim the archived log space.使用RMAN交叉检查命令回收归档记录空间。(自动)

D.Use OS command to move files from the flash recovery area to some other location使用操作系统命令将文件从闪回恢复区移动到其他位置

Use the CROSSCHECK command to synchronize the physical reality of backups and copies with their logical records in the RMAN repository.

The CROSSCHECK command does not delete the repository records of the files that it does not find,but updates their repository records to EXPIRED.You can run DELETE EXPIRED to remove the repository records for expired files and any existing physical files whose status is EXPIRED.

 

 

使用OS命令来移动备份文件,再使用CROSSCHECK来检查物理与逻辑备份是否一致,如果出现EXPIRED状态,则通过DELETE EXPIRED删除过期的备份,即在物理磁盘上没有备份文件。这样就可以个FRA腾出更多的空间。

EXPIRED)

 

28.You have a range-partitioned table in your database.Each partition in the table contains the sales data for a quarter.

The partition related to the current quarter is modified frequently and other partitions undergo fewer data manipulations.The preferences for the table are set to their default values.You collect statistics for the table using the following command in regular intervals:

SQL>EXECUTE

DBMS_STATS.GATHER_TABLE_STATS('SH','SALES',GRANULARITY=>'GLOBAL');

You need statistics to be collected more quickly.What can you do to achieve this?

A.Set DYNAMIC_SAMPLING to level 4.

  1. Set the STATISTICS_LEVEL parameter to BASIC.
  2. Set the INCREMENTAL value to TRUE for the partition table.

D.Increase the value of STALE_PERCENT for the partition table.

Answer:C

答案解析:

(Incremental Statistic Setting

It's easy to change the statistic strategy for big partition table in Oracle 11g.Using the package dbms_stats will help setting the parameters.

The default strategy for Oracle partition table is not incremental setting.Only three parameters will affect the behavior.

SQL>select dbms_stats.get_prefs('PUBLISH','SYS','T_PART')from dual;

DBMS_STATS.GET_PREFS('PUBLISH'

--------------------------------------------------------------------------------

TRUE

SQL>select dbms_stats.get_prefs('INCREMENTAL','SYS','T_PART')from dual;

DBMS_STATS.GET_PREFS('INCREMEN

--------------------------------------------------------------------------------

FALSE

SQL>select dbms_stats.get_prefs('GRANULARITY','SYS','T_PART')from dual;

DBMS_STATS.GET_PREFS('GRANULAR

--------------------------------------------------------------------------------

AUTO)

29.Which two statements are true regarding the Automatic Diagnostic Repository(ADR)in Oracle

Database 11g?(Choose two.)

A.A single ADR can support multiple ADR homes for different database instances.

B.The alert files are stored in XML file format in the TRACE directory of each ADR home.

C.If the environmental variable ORACLE_BASE is set,then DIAGNOSTIC_DEST is set to

$ORACLE_BASE.

D.The BACKGROUND_DUMP_DEST initialization parameter overrides the DIAGNOSTIC_DEST

initialization parameter for the location of the alert log file.

Answer:AC

答案解析:

(关于Oracle数据库11g中的自动诊断信息库(ADR)哪两个陈述是真实的?

Automatic Diagnostic Repository.A a file-based hierarchical data store for managing diagnostic information,including network tracing and logging.

A.A single ADR can support multiple ADR homes for different database instances.

单个的自动诊断信息库可以支持多个用于不同的数据库实例的自动诊断信息库家目录。

C.If the environmental variable ORACLE_BASE is set,then DIAGNOSTIC_DEST is set to$ORACLE_BASE.

如果ORACLE_BASE环境变量已设置,则DIAGNOSTIC_DEST被设置为$ORACLE_BASE

参考:http://docs.oracle.com/cd/E11882_01/server.112/e25494/diag.htm#ADMIN11008

the ADR root directory is known as ADR base.Its location is set by the DIAGNOSTIC_DEST initialization parameter.If this parameter is omitted or left null,the database sets DIAGNOSTIC_DEST upon startup as follows:

If environment variable ORACLE_BASE is set,DIAGNOSTIC_DEST is set to the directory designated by ORACLE_BASE.

If environment variable ORACLE_BASE is not set,DIAGNOSTIC_DEST is set to ORACLE_HOME/log

Within ADR base,there can be multiple ADR homes,where each ADR home is the root directory for all diagnostic data—traces,dumps,the alert log,and so on—for a particular instance of a particular Oracle product or component.For example,in an Oracle Real Application Clusters environment with Oracle ASM,each database instance,Oracle ASM instance,and listener has an ADR home.

来源:<http://docs.oracle.com/cd/E11882_01/server.112/e25494/diag.htm#ADMIN13159>)

 

30.Which two statements are true with respect to the maintenance window?(Choose two.)

A.A DBA can enable or disable an individual task in all maintenance windows.

B.A DBA cannot change the duration of the maintenance window after it is created.

C.In case of a long maintenance window,all Automated Maintenance Tasks are restarted every four

hours.

D.A DBA can control the percentage of the resource allocated to the Automated Maintenance Tasks in each window.

Answer:AD

答案解析:

(Managing Automatic System Tasks Using the Maintenance Window

Oracle Database is preconfigured to perform some routine database maintenance tasks so that you can run them at times when the system load is expected to be light.You can specify for such a time period a resource plan that controls the resource consumption of those maintenance tasks.When the designated time period ends,the database can switch to a different resource plan that lowers the resource allocation for any remaining maintenance tasks.)

 

来自 “ ITPUB博客 ” ,链接:http://blog.itpub.net/26736162/viewspace-1216100/,如需转载,请注明出处,否则将追究法律责任。

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