You work as a database administrator for Supportcenter.cn. You find that reports are running for a long time in your data warehousing applications. You suspect a lack of indexes is the reason for the performance degradation. Which advisory component would you refer to， in order to determine the appropriate indexes？（）

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

单项选择题YouworkasadatabaseadministratorforSupportcenter.cn.Inaproductionenvironment，userscomplainabouttheslowresponsetimewhenaccessingthedatabase.YouhavenotoptimizedthememoryusageoftheOracleinstanceandyoususpecttheproblemtobewiththememory.Towhichtypeofobjectwouldyourefertodeterminethecauseoftheslowresponse？（）

A.The trace file
B.The fixed views
C.The data dictionary views
D.The operating system log fields
E.The dynamic performance views.

单项选择题YouworkasadatabaseadministratorforSupportcenter.cn.Thedatabaseisopen.Amediafailurehasoccurred，resultinginlossofallthecontrolfilesinyourdatabase.Whichstatementregardingthedatabaseinstanceistrueinthisscenario？（）

A.The instance would hang.
B.The instance needs to be shut down.
C.The instance would be in the open state.
D.The instance would abort in such cases.
E.The instance would be in the open and invalid state.
F.The instance would in the open state， but all the background processes will be restarted.

多项选择题Youareworkingonatestdatabasewhereinstancerecoverytakesaconsiderableamountoftime.Howcanreducetherecoverytime？（）

A.By multiplexing the control files
B.By multiplexing the redo log files
C.By decreasing the size of redo log files
D.By configuring mean time to recover （MTTR） to a lower value
E.By setting the UNDO_RETENTION parameter to a higher value