oracle位图索引

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1、WhataDBANeedstoKnowAboutOracle’sBitmapIndexingtoRetrieveDataQuickly?PartIVilinRoufchaieCingularWirelessvilin.roufchaie@cingular.comveeleen@yahoo.comDownloadslides:www.nocoug.org2021/7/121PresentationAssumptions&PrerequisitesFamiliaritywithbasicDatabaseandDataWarehouseconcepts

2、isrequiredBitmapandBitVectorwillbeusedinterchangeably2021/7/122WhoIsThisPresentationFor?Datawarehousedesigners&developersDBAsPerformanceDBAsCapacityPlanners2021/7/123PresentationSummaryPartIOverview,Characteristics,Structure&SizeofaBitmapIndexPerformanceConsiderationsofBitmapIn

3、dexingLogicalLayoutofBitmapIndexesBitmapIndexCreation&StorageIssuesQueryProcessing&BitmapIndexAccessPaths2021/7/124PresentationSummaryPartIIStarSchema,Join,&TransformationStarOptimization,andTransformationCBOEstimation&QueryTransformerEnablingStarTransformationStarTransformatio

4、nSteps2021/7/125PresentationSummaryPartIIJoinbackEliminationCaseStudy&ExplainPlanReviewTo“StarQuery”?OrTo“StarTransform”?ConclusionsAcknowledgements2021/7/126IndexingRules-of-ThumbInbuildinganindexknow:dataselectivity,datadistribution,workload,executionplan,proofofutilization

5、.Thereiscost&overheadinbuilding,utilizing,tuning,&maintainingindexesofanysort!Whatdoweexpectafterpayingthosecost?2021/7/127IndexingRules-of-ThumbPerformance!Ordersofmagnitudeinexecutionspeed?Ideal!!HowaboutwhatmakestheBusiness/usershappy!Makesurebusinessexpectationsareunderstood

6、&adequateresearch&testsaredonetoassessthelikelihoodofsucceedingbeforecommittingtosomething2021/7/128IndexingRules-of-ThumbTheindexmustbebeneficialtoallSQL'simpactedbyitacrosstheboard--WhollybeneficialTryAggregate/CollectivetuningSowewanttobuildfew,efficientindexesDemand:Low-over

7、headindexes,requiringlessfrequent&fastre/builds,&bespace-efficient2021/7/129OverviewOfBitmapIndexingBitmapindexingisaqueryexecutionoptimizationtechniqueinDataWarehousingenvironmentsOracleprovidesOLTP&DataWarehousinginoneengine2021/7/1210OverviewOfBitmapIndexingOracleSupportsEver

8、-growingTypesofIndexes:B*-treeB*-treeClusterHas