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ID:51969298
大小:1.65 MB
页数:53页
时间:2020-03-26
《数据库系统概念全套配套课件PPT ch26.ppt》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、Chapter26:AdvancedTransactionProcessingChapter26:AdvancedTransactionProcessingTransaction-ProcessingMonitorsTransactionalWorkflowsHigh-PerformanceTransactionSystemsMainmemorydatabasesReal-TimeTransactionSystemsLong-DurationTransactionsTransactionmanageme
2、ntinmultidatabasesystemsTransactionProcessingMonitorsTPmonitorsinitiallydevelopedasmultithreadedserverstosupportlargenumbersofterminalsfromasingleprocess.Provideinfrastructureforbuildingandadministeringcomplextransactionprocessingsystemswithalargenumbero
3、fclientsandmultipleservers.Provideservicessuchas:PresentationfacilitiestosimplifycreatinguserinterfacesPersistentqueuingofclientrequestsandserverresponsesRoutingofclientmessagestoserversCoordinationoftwo-phasecommitwhentransactionsaccessmultipleservers.S
4、omecommercialTPmonitors:CICSfromIBM,PathwayfromTandem,TopEndfromNCR,andEncinafromTransarcTPMonitorArchitecturesTPMonitorArchitectures(Cont.)Processperclientmodel-insteadofindividualloginsessionperterminal,serverprocesscommunicateswiththeterminal,handlesa
5、uthentication,andexecutesactions.MemoryrequirementsarehighMultitasking-highCPUoverheadforcontextswitchingbetweenprocessesSingleprocessmodel-allremoteterminalsconnecttoasingleserverprocess.Usedinclient-serverenvironmentsServerprocessismulti-threaded;lowco
6、stforthreadswitchingNoprotectionbetweenapplicationsNotsuitedforparallelordistributeddatabasesTPMonitorArchitectures(Cont.)Many-serversingle-routermodel-multipleapplicationserverprocessesaccessacommondatabase;clientscommunicatewiththeapplicationthroughasi
7、nglecommunicationprocessthatroutesrequests.IndependentserverprocessesformultipleapplicationsMultithreadserverprocessRunonparallelordistributeddatabaseManyservermany-routermodel-multipleprocessescommunicatewithclients.Clientcommunicationprocessesinteractw
8、ithrouterprocessesthatroutetheirrequeststotheappropriateserver.Controllerprocessstartsupandsupervisesotherprocesses.DetailedStructureofaTPMonitorDetailedStructureofaTPMonitorQueuemanagerhandlesincomingmessagesSomequeuemana
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