高级数据库技术-The Tukwila Data Integration System

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1、TheTukwilaDataIntegrationSystemUniversityofWashingtonContentTukwilaArchitectureAdaptiveQueryExecutionTheNeedforAdaptivityInterleavingPlanningandExecutionAdaptiveQueryOperatorsImplementationTheworknextTukwilaArchitectureTukwilaArchitectureClient/userinterfaceUserposesqueriesin

2、termsofmediatedrelationalschema.ThequerysarefedtothereformulatorTukwilaArchitectureReformulatorMiniCon,mappingtheinputqueryfromthemediatedschematothedatasources.Usedatasourcecatalog.TukwilaArchitectureDatasourcecatalogMappingsfromtheavailabledatasourcestothemediatedschema.Ove

3、rlapinformationaboutpairsofDataSources.Estimatedaccesscosts,sizesofrelations,etc.TukwilaArchitectureOptimizerSpecifypartialplansIncrementallyre-optimizeaqueryGeneratesevent-condition-actionrulesTukwilaArchitectureAdaptivequeryexecutionengineOperatorExecutionprocessesqueryplan

4、sEventHandlerfordynamicallyinterpretingruleTukwilaArchitectureWrappersAvailableforODBC-compliant.TranslatedataformatsLocation-independentAdaptiveQueryExecutionTheNeedforAdaptivityAbsenceofstatisticsCardinalities/histogramsUnpredictabledataarrivalcharacteristicsInitialdelaysbe

5、foredataarrivalBurstyarrivalsofdatathereafterOverlapandredundancyamongsourcessloworunavailabledatasourcescanoftenbereplacedbyoverlappingormirroredsourcesAdaptiveQueryExecutionInterleavingPlanningandExecutionQueryPlansQueryExecutionEventHandlingAdaptiveQueryExecutionQueryPlans

6、MakeupApartially-setoffragmentsAglobalruleProcessFragmentsinpartialorderexecuteintheorderFragmentsunrelatedinpartialorderexecuteinparallelTheendofafragmentResultsarematerializedTherestoftheplancanbere-optimizedorrescheduledChoosenextfragmentbyruleorpartialorderQueryPlansFragm

7、entsandOperatorsFragmentAfullypipelinedtreeofphysicaloperatorsAsetoflocalrulesOperatorAlgebraic:selection,join…Chosenphysicalimplementation:doublepipelinedjoin…childrenthenode:Memoryallocated:QueryPlansRulesRe-optimizationCardinalityestimatesignificantlydifferfromactualsizeEn

8、dofafragmentContingentplanningWhichfragmenttoselectEndofafragmentAda