45 个LoadRunner英文面试笔试问题附答案2文档格式.docx

45 个LoadRunner英文面试笔试问题附答案2文档格式.docx

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22、Howdoyouperformfunctionaltestingunderload?

-FunctionalityunderloadcanbetestedbyrunningseveralVusersconcurrently.ByincreasingtheamountofVusers,wecandeterminehowmuchloadtheservercansustain.

23、WhatisRampup?

Howdoyousetthis?

-ThisoptionisusedtograduallyincreasetheamountofVusers/loadontheserver.Aninitialvalueissetandavaluetowaitbetweenintervalscanbe

specified.TosetRampUp,gotoScenarioSchedulingOptions

24、WhatistheadvantageofrunningtheVuserasthread?

-VuGenprovidesthefacilitytousemultithreading.ThisenablesmoreVuserstoberunpergenerator.IftheVuserisrunasaprocess,thesamedriverprogramisloadedintomemoryforeachVuser,thustakingupalargeamountofmemory.ThislimitsthenumberofVusersthatcanberunonasinglegenerator.IftheVuserisrunasathread,onlyoneinstanceofthedriverprogramisloadedintomemoryforthegivennumberofVusers（say100）.Eachthreadsharesthememoryoftheparentdriverprogram,thusenablingmoreVuserstoberunpergenerator.

25、Ifyouwanttostoptheexecutionofyourscriptonerror,howdoyoudothat?

-Thelr_abortfunctionabortstheexecutionofaVuserscript.ItinstructstheVusertostopexecutingtheActionssection,executethevuser_endsectionandendtheexecution.Thisfunctionisusefulwhenyouneedtomanuallyabortascriptexecutionasaresultofaspecificerrorcondition.Whenyouendascriptusingthisfunction,theVuserisassignedthestatusStopped.Forthistotakeeffect,wehavetofirstunchecktheContinueonerroroptioninRun-TimeSettings.

26、WhatistherelationbetweenResponseTimeandThroughput?

-TheThroughputgraphshowstheamountofdatainbytesthattheVusersreceivedfromtheserverinasecond.Whenwecomparethiswiththetransactionresponsetime,wewillnoticethatasthroughputdecreased,theresponsetimealsodecreased.Similarly,thepeakthroughputandhighestresponsetimewouldoccurapproximatelyatthesametime.

27、ExplaintheConfigurationofyoursystems?

-TheconfigurationofoursystemsreferstothatoftheclientmachinesonwhichweruntheVusers.Theconfigurationofanyclientmachineincludesitshardwaresettings,memory,operatingsystem,softwareapplications,developmenttools,etc.Thissystemcomponentconfigurationshouldmatchwiththeoverallsystemconfigurationthatwouldincludethenetworkinfrastructure,thewebserver,thedatabaseserver,andanyothercomponentsthatgowiththislargersystemsoastoachievetheloadtestingobjectives.

28、Howdoyouidentifytheperformancebottlenecks?

-PerformanceBottleneckscanbedetectedbyusingmonitors.Thesemonitorsmightbeapplicationservermonitors,webservermonitors,databaseservermonitorsandnetworkmonitors.Theyhelpinfindingoutthetroubledareainourscenariowhichcausesincreasedresponsetime.Themeasurementsmadeareusuallyperformanceresponsetime,throughput,hits/sec,networkdelaygraphs,etc.

29、Ifwebserver,databaseandNetworkareallfinewherecouldbetheproblem?

-Theproblemcouldbeinthesystemitselforintheapplicationserverorinthecodewrittenfortheapplication.

30、Howdidyoufindwebserverrelatedissues?

-UsingWebresourcemonitorswecanfindtheperformanceofwebservers.Usingthesemonitorswecananalyzethroughputonthewebserver,numberofhitspersecondthatoccurredduringscenario,thenumberofhttpresponsespersecond,thenumberofdownloadedpagespersecond.

31、Howdidyoufinddatabaserelatedissues?

-ByrunningDatabasemonitorandhelpofDataResourceGraphwecanfinddatabaserelatedissues.E.g.Youcanspecifytheresourceyouwanttomeasureonbeforerunningthecontrollerandthanyoucanseedatabaserelatedissues

32、Explainallthewebrecordingoptions?

33、WhatisthedifferencebetweenOverlaygraphandCorrelategraph?

-OverlayGraph:

Itoverlaythecontentoftwographsthatsharesacommonx-axis.LeftY-axisonthemergedgraphshowsthecurrentgraphsvalueRightY-axisshowthevalueofY-axisofthegraphthatwasmerged.CorrelateGraph:

PlottheY-axisoftwographsagainsteachother.TheactivegraphsY-axisbecomesX-axisofmergedgraph.Y-axisofthegraphthatwasmergedbecomesmergedgraphsY-axis.

34、HowdidyouplantheLoad?

WhataretheCriteria?

-Loadtestisplannedtodecidethenumberofusers,whatkindofmachineswearegoingtouseandfromwheretheyarerun.Itisbasedon2importantdocuments,TaskDistributionDiagramandTransactionprofile.TaskDistributionDiagramgivesustheinformationonnumberofusersforaparticulartransactionandthetimeoftheload.Thepeakusageandoff-usagearedecidedfromthisDiagram.Transactionprofilegivesustheinformationaboutthetransactionsnameandtheirprioritylevelswithregardtothescenariowearedeciding.

35、Whatdoesvuser_initactioncontain?

-Vuser_initactioncontainsprocedurestologintoaserver.

36、Whatdoesvuser_endactioncontain?

-Vuser_endsectioncontainslogoffprocedures.

37、Whatisthinktime?

Howdoyouchangethethreshold?

-Thinktimeisthetimethatarealuserwaitsbetweenactions.Example:

Whenauserreceivesdatafromaserver,theusermaywaitseveralsecondstoreviewthedatabeforeresponding.Thisdelayisknownasthethinktime.ChangingtheThreshold:

Thresholdlevelisthelevelbelowwhichtherecordedthinktimewillbeignored.Thedefaultvalueisfive（5）seconds.WecanchangethethinktimethresholdintheRecordingoptionsoftheVugen.

38、Whatisthedifferencebetweenstandardlogandextendedlog?

-Thestandardlogsendsasubsetoffunctionsandmessagessentduringscriptexecutiontoalog.ThesubsetdependsontheVusertypeExtendedlogsendsadetailedscriptexecutionmessagestotheoutputlog.Thisismainlyusedduringdebuggingwhenwewantinformationabout:

Parametersubstitution.Datareturnedbytheserver.Advancedtrace.

39、Explainthefollowingfunctions:

-lr_debug_message-Thelr_debug_messagefunctionsendsadebugmessagetotheoutputlogwhenthespecifiedmessageclassisset.lr_output_message-Thelr_output_messagefunctionsendsnotificationstotheControllerOutputwindowandtheVuserlogfile.lr_error_message-Thelr_error_messagefunctionsendsanerrormessagetotheLoadRunnerOutputwindow.lrd_stmt-Thelrd_stmtfunctionassociatesacharacterstring（usuallyaSQLstatement）withacursor.ThisfunctionsetsaSQLstatementtobeprocessed.lrd_fetch-Thelrd_fetchfunctionfetchesthenextrowfromtheresultset.

40、Throughput

-IfthethroughputscalesupwardastimeprogressesandthenumberofVusersincrease,thisindicatesthatthebandwidthissufficient.IfthegraphweretoremainrelativelyflatasthenumberofVusersincreased,itwouldbereasonabletoconcludethatthebandwidthisconstrainingthevolumeofdatadelivered.

41、TypesofGoalsinGoal-

OrientedScenario-LoadRunnerprovidesyouwithfivedifferenttypesofgoalsinagoalorientedscenario:

ThenumberofconcurrentVusers

Thenumberofhitspersecond

Thenumberoftransactionspersecond

Thenumberofpagesperminute

Thetransactionresponsetimethatyouwantyourscenario

42、AnalysisScenario（Bottlenecks）:

InRunningVusergraphcorrelatedwiththeresponsetimegraphyoucanseethatasthenumberofVusersincreases,theaverageresponsetimeofthecheckitinerarytransactionverygraduallyincreases.Inotherwords,theaverageresponsetimesteadilyincreasesastheloadincreases.At56Vusers,thereisasudden,sharpincreaseintheaverageresponse

time.Wesaythatthetestbroketheserver.Thatisthemeantimebeforefailure（MTBF）.Theresponsetimeclearlybegantodegradewhenthereweremorethan56Vusersrunningsimultaneously.

43、Whatiscorrelation?

Explainthedifferencebetweenautomaticcorrelationandmanualcorrelation?

-

Correlationisusedtoobtaindatawhichareuniqueforeachrunofthescriptandwhicharegeneratedbynestedqueries.Correlationprovidesthevaluetoavoiderrorsarisingoutofduplicatevaluesandalsooptimizingthecode（toavoidnestedqueries）.Automaticcorrelationiswherewesetsomerulesforcorrelation.Itcanbeapplicationserverspecific.Herevaluesarereplacedbydatawhicharecreatedbytheserules.Inmanualcorrelation,thevaluewewanttocorrelateisscannedandcreatecorrelationisusedtocorrelate.

44、Wheredoyousetautomaticcorrelationoptions?

-Automaticcorrelationfromwebpointofview,canbesetinrecordingoptionsandcorrelationtab.Herewecanenablecorrelationfortheentirescriptandchooseeitherissueonlinemessagesorofflineactions,wherewecandefinerulesforthatcorrelation.Automaticcorrelationfordatabase,canbedoneusingshowoutputwindowandscanforcorrelationandpickingthecorrelatequerytabandchoosewhichqueryvaluewewanttocorrelate.Ifweknowthespecificvaluetobecorrelated,wejustdocreatecorrelationforthevalueandspecifyhowthevaluetobecreated.

45、Whatisafunctiontocapturedynamicvaluesinthewebvuserscript?

-Web_reg_save_paramfunctionsavesdynamicdatainformationtoaparameter.