多项选择题
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 YouworkasadatabaseadministratorforCertkiller.com.UsersintheCertkiller.comPRODdatabasecomplainabouttheslowresponseoftransactions.Whileinvestigatingthereasonyoufindthatthetransactionsarewaitingfortheundosegmentstobeavailable，andundoretentionhasbeensettozero.Whatwouldyoudotoovercomethisproblem？（）
单项选择题 YouworkasadatabaseadministratorforCertkiller.com.WhileloadingdataintotheCertkillerSTAFFtableusingOracleEnterpriseManager10gDatabaseControl，youfindthestatusofthejobasfailed.Onfurtherinvestigation，youfindthefollowingerrormessageintheoutputlog：ORA-01653unabletoextendtableHR.CertkillerSTAFFby8intablespaceUSERSWhichtaskwouldyouperformtoloadthedatasuccessfullywithoutaffectingtheuserswhoareaccessingthetable？（）
单项选择题 InyourCertkiller.comdatabaseservertheparameterPLSQL_CODE_TYPEhasbeensettoNATIVE.Whichobjectwouldbeachievedbythesetting？（）