单项选择题 Yourdatabaseisfunctionalwithpeakloadforonehour.Youwanttopreservetheperformancestatisticscollectedduringthisperiodsothattheycanbeusedforcomparisonwhileanalyzingtheperformanceofthedatabaseinthefuture.Whatactionwouldyoutaketoachievethistask？（）A.SettheSTATISTICS_LEVELinitializationparametertoALL.B.Createabaselineonapairofsnapshotsthathavethestatisticsofthepeak-loadperiodinthedatabase.C.DecreasethesnapshotintervalintheAWRtocollectmorenumberofsnapshotsduringthepeak-loadperiod.D.SetthesnapshotretentionperiodintheAutomaticWorkloadRepository（AWR）tozerotoavoidtheautomaticpurgingofthesnapshots.

单项选择题 YouaremaintainingyourOLTPdatabaseinOracle10g.Whileobservingtheperformanceofthedatabase，youfindthatthelogswitchoccursmorethanonceforevery20minutes，affectingthedatabaseperformance.Whichfactorisresponsibleforfrequentlogswitches？（）A.thevalueoftheUNDO_RETENTIONinitializationparameterB.thevalueoftheoptimalredologfilesizeprovidedbytheRedoLogfileSizeAdvisorC.theonlineredologfilessizeD.thenumberofredologmembersinagroup

单项选择题 BtoB电子商务指的是().