You work as a database administrator for Supportcenter.cn. In a production environment， users complain about the slow response time when accessing the database. You have not optimized the memory usage of the Oracle instance and you suspect the problem to be with the memory. To which type of object would you refer to determine the cause of the slow response？（）

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

单项选择题You work as a database administrator for Supportcenter.cn. Users in the Supportcenter.cn PROD database complain about the slow response of transactions. While investigating the reason you find that the transactions are waiting for the undo segments to be available， and undo retention has been set to zero.  What would you do to overcome this problem？（）

A.Increase the undo return
B.Create more undo segments
C.Create another undotablespace
D.Increase the size of the undo tablespace

单项选择题InyourSupportcenter.cndatabaseservertheparameterPLSQL_CODE_TYPEhasbeensettoNATIVE.Whichobjectwouldbeachievedbythesetting？（）

A.The source PL/SQL code will be stored in native machine code.
B.The source PL/SQL code will be stored in interpreted byte code.
C.The compiled PL/SQL code will be stored in native machine code.
D.The compiled PL/SQL code will be stored in interpreted byte code.

单项选择题YouworkasadatabaseadministratorforSupportcenter.cn.OnaMondaymorning，youfindthedatabaseinstanceaborted.Afterinspectingthealertlogfile，youexecutetheSTARTUPcommandinSQL*Plustobringtheinstanceup.Whatstatementistrue？（）

A.PMON coordinates media recovery.
B.SMON coordinates instance recovery.
C.PMON coordinates instance recovery.
D.Undo Advisor would roll back all uncommitted transactions.
E.SQL*PLUS reports an error with the message asking you to perform instance recovery.