数据仓库中基于访问频率的动态物化视图的研究

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1、山东大学硕士学位论文数据仓库中基于访问频率的动态物化视图的研究姓名：衣振萍申请学位级别：硕士专业：计算机应用技术指导教师：潘景昌20050415山东大学硕士学位论文只有临时物化视图才可以被调整，从而避免了具有较高稳定访问频率的物化视图被删除。物化视图预警线(PWL，PriorWarningLine)的引入，可以提前发现物化视图存储空间即将被填满的状态，提前进行物化视图调整前的准备，从而提高系统响应查询的效率。本文提出了动态物化选择及调整的核心算法，采用TPC—H基准数据模式、用IGB的数据构造和填充了Oracle数据仓库，以此为基础进行实验查询和分析对比，实验验证了收益

2、模型和动态物化调整算法的有效性。本文提出了动态物化视图方案具有自适应、高效、易操作的特点，但要将其完全应用于数据仓库中，还需要考虑与其它机制的协调，以及一些集成的细节，这也是下一步要研究的内容。关键词：数据仓库，物化视图选择，动态，自适应一些查盔堂堡主堂垡笙苎BasedonAccessingFrequencyDynamicMaterializationViewsinDataWarehousesAbstractIndatawarehouseenvironment,0LAP(On-LineAnalyticalProcessing)andOLDM(On。LineAnalyti

3、calMining)usuallyuseconciseresults，whicharecomputedfromhugebasedata,to．answerqueriescommittedbyusers．Becauseofthispoint，Materializedviewsarcofunprecedentedimportanceindatawarehouses．Indatawarehouses，materializedviewsareusedtopre—computeandstoreaggregateddatasuchassumsandaverages，fromwhic

4、hanswerstoqueriesaremadethroughsimplesearchorsimplecomputation，consequentlymaterializedviewsCallremarkablyspeeduptheresponsetoqueriescommitted．However，materializedviewsneedspacetostoreandneedbeingmaintained．Asaresultmaterializingallviewsisunpractical．Theremustbesomestrategytoselectoutwha

5、tshouldbematerialized，whichiscalledMVS(MaterializedViewsSelection)．TherehavebeenalotofstudieswhichfocusonMVS，whereastheycannotmeetthestabilityandtherobustcharacter，whichcountagreatdealinthepracticeofindustry．ThecurrentdatawarehouseproductsCannotsoundlysupportmaterializedviewsauto—selecti

6、on：WhattheyadoptarestaticapproacheswhichgreatlydisobeydynamicnatureofOLAPandDSS．However,thefutureofdatawarehousedemandsMVSmoreonitsefficiency，tractability，validityandadaptable．Thisdissertationputsforsvardadynamicmaterializationviewsapproachwhichisbasedonviewsaccessingfrequencies．Compared

7、tOtraditionalstaticMVSapproach，thedynamicapproachdescribedhereismoreadaptable，moreefficientandmoretractable．Itisabletosolvelarge·scaleMVSproblemTheapproachmaterializeviewsindifferentphasesandindifferentwayaccordingtOtheirdifferentaccessingrequirements，whichreducesthecompl