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1、为了适应公司新战略的发展，保障停车场安保新项目的正常、顺利开展，特制定安保从业人员的业务技能及个人素质的培训计划sql,server,执行计划,缓存 看懂执行计划 例子1 以AdventureWorks的DatabaseLog查询为例： SELECT*FROM[AdventureWorksXXR2].[dbo].[DatabaseLog] ?Cachedplansize–howmuchmemorytheplangeneratedbythisquerywilltakeupinstoredprocedurecache.Thisisausefulnumberwh
2、eninvestigatingcacheperformanceissuesbecauseyou'llbeabletoseewhichplansaretakingupmorememory. ?EstimatedOperatorCost–we'vealreadyseenthisasthepercentagecostinFigure1. ?EstimatedSubtreeCost–tellsustheaccumulatedoptimizercostassignedtothisstepandallprevioussteps,butremembertoreadfromri
3、ghttoleft.Thisnumberismeaninglessintherealworld,butisamathematicalevaluationusedbythequeryoptimizertodeterminethecostoftheoperatorinquestion;itrepresentstheamountoftimethattheoptimizerthinksthisoperatorwilltake. ?目的-通过该培训员工可对保安行业有初步了解，并感受到安保行业的发展的巨大潜力，可提升其的专业水平，并确保其在这个行业的安全感。为了适应公司新战略
4、的发展，保障停车场安保新项目的正常、顺利开展，特制定安保从业人员的业务技能及个人素质的培训计划 Estimatednumberofrows –calculatedbasedonthestatisticsavailabletotheoptimizerforthetableorindexinquestion. Thelogicaloperatorsaretheresultsoftheoptimizer'scalculationsforwhatshouldhappenwhenthequeryexecutes.Thephysicaloperatorsrepresent
5、whatactuallyoccurred.Thelogicalandphysicaloperatorsareusuallythesame,butnotalways TheSubtreeissimplythesectionoftheexecutiontreethatwehavelookedatsofar,workingrighttoleftagain,andtoptobottom.Allestimationsarebasedonthestatisticsavailableonthecolumnsandindexesinanytable. TheI/OCostand
6、CPUcostarenotactualoperators,butratherthecostnumbersassignedbytheQueryOptimizerduringitscalculations.Thesenumbersareusefulwhendetermining目的-通过该培训员工可对保安行业有初步了解，并感受到安保行业的发展的巨大潜力，可提升其的专业水平，并确保其在这个行业的安全感。为了适应公司新战略的发展，保障停车场安保新项目的正常、顺利开展，特制定安保从业人员的业务技能及个人素质的培训计划 whethermostofthecostisI/O-ba
7、sed(asinthiscase),orifwe'reputtingaloadontheCPU.Abiggernumbermeansmoreprocessinginthisarea. You'llnotethat,inthiscase,theoperatorcostandthesubtreecostarethesame,sincethetablescanistheonlyoperator.Formorecomplextrees,withmoreoperators,you'llseethatthecostaccumulatesastheindividualcos
