You work as a database administrator for Supportcenter.cn. Users in the SupportCenter PROD database complain about the slow response when accessing the database. In the Active Session Waiting： Configuration page you find that the majority of the wait time is for the redo log buffer. Further investigation using the Run Queue graph and operating system tools reveals that the redo log files are on the same disks， and that the disk I/O for the redo log files is the reason for the performance degradation. 
Which two actions would you take to gain performance？（）

单项选择题Initially，fortheAutomaticWorkloadRepository（AWR）statistics，theretentionperiodissetto7days，thecollectionintervalissetto30minutesandthecollectionlevelissettoTypicalinyourproductiondatabase.YouhavebeenusingtheMemoryAdvisorforthelastthreemonthstogeneraterecommendationsfortuningmemorycomponents.However，whenyouobservetheMemoryAdvisoronaFriday，youfindthatthestatisticsareavailableonlyfortwodays，ThursdayandFriday，ofthatweek.Whatwouldhavecausedthestatisticstoberemoved？（）

A.On Wednesday， the statistics have been purged.
B.On Wednesday， the retention period has been set to zero.
C.On Wednesday， the collection interval has been set to zero.
D.On Wednesday， the collection level has been changed to All.
E.On Wednesday， the retention period has been set to one day.
F.On Wednesday， the retention period has been set to two days
G.On Wednesday, the collection level has been changed to Typical.
H.On Wednesday, the collection interval has been set to 1440 minutes.

单项选择题Inyourdatabaseserver，theparameterPLSQL_OPTIMIZE_LEVELhasbeensetto2.Whatwouldthissettingachieve？（）

A.It degrades the run time and compiler performance.
B.It provides better run time and compiler performance.
C.It provides better optimization of the statement during parse time.
D.It forces the rule based optimizer to be used for statement optimization.
E.It provides better run time performance but slightly degraded compiler performance.
F.It provides better run time performance but slightly degraded run time performance.

单项选择题YouworkasadatabaseadministratorforSupportcenter.cn.Youfindthatreportsarerunningforalongtimeinyourdatawarehousingapplications.Yoususpectalackofindexesisthereasonfortheperformancedegradation.Whichadvisorycomponentwouldyoureferto，inordertodeterminetheappropriateindexes？（）

A.Memory Advisors
B.Segment Advisors
C.SQL Tuning and Access Advisors
D.Automated Workload Repository （AWR）
E.Automatic Database Diagnostic Monitor （ADDM）

单项选择题Twodatabaseusers,JackandBill,areaccessingtheSupportCenterSTAFFtableoftheSupportCenterDBdatabase.WhenJackmodifiesavalueinthetable,thenewvalueisinvisibletoBill.WhichisthemodifiedvalueinvisibletoBill?（）

A.The modified data are not available on disk.
B.The modified data have been flushed out from memory.
C.The modified rows of the SupportCenter STAFF table have been locked.
D.Jack has not committed the changes after modifying the value.
E.Both users are accessing the database from two different machines.

多项选择题YouworkasadatabaseadministratorforSupportcenter.cn.YouhavesettheretentionperiodforAutomaticRepository（AWR）statisticstofourdaysandcollectionintervalto15minutes.YouwanttoviewthestatisticscollectedandstoredinAWRsnapshot.WhichtwomethodswouldyouusetoviewtheAWRstatistics？（）

A.use enterprise manager
B.use DBMS_SQL package
C.use DBMS_AWR package
D.use PRVT_WORKLOAD package
E.query the AWR snapshot repository objects
F.use DBMS_WORKLOAD_REPOSITORY package