Isolation-only Transactions by Typing and Versioning_百度文库
Isolation-only Transactions by Typing and Versioning
Isolation-onlyTransactionsbyTypingandVersioning
EcolePolytechniqueF?ed?eraledeLausanne(EPFL)
1015Lausanne,Switzerland
Pawe?T.Wojciechowski
Pawel.Wojciechowski@epfl.ch
Inthispaperwedesignalanguageandruntimesupportforisolation-only,multithreadedtransactions(calledtasks).Tasksallowisolationtobedeclaredinsteadofhavingtobeencodedusingthelow-levelsynchronizationconstructs.Thekeyconceptofourdesignistheuseofatypesystemtosupportrollback-freeandsaferuntimeexecutionoftasks.Wepresentafirst-ordertypesystemwhichcanverifyin-formationfortheconcurrencycontroller.Weuseanopera-tionalsemanticstoformalizeandprovethetypesoundnessresultandanisolationpropertyoftasks.Thesemanticsusesaspecializedconcurrencycontrolalgorithm,thatisbasedonaccessversioning.
CategoriesandSubjectDescriptors:D.3.3[Program-mingLanguages]:LanguageConstructsandFeatures—Abstractdatatypes,ConcurrentprogrammingstructuresGeneralTerms:Design,Languages,Reliability,Theory,Verification.
Keywords:programminglanguages,concurrency,typetheory,transactions,isolation,declarativesynchronization,abstracttypes,singletonkinds,lambdacalculus.
1.INTRODUCTION
Multithreadinghasbecomeanessentialpartofmodernsoftwaresystems.Althoughthreadssimplifytheprogram’sconceptualdesignandallowparallelismonmultipleproces-sors,theyalsoincreaseprogrammingcomplexity.Program-mersmustensurethatthreadsaccessingshareddatain-teractcorrectly,whichisnotoriouslyadifficulttask.Itisnaturaltoaskwhethertransactions[32,2]theymaintaintheillusionofexclusiveaccesstothewholedatasetwhilepermittingconcurrentaccessatafinelevel.Whiletherehavebeenavarietyofimplementationsoftransactions(see[7,8,33,14,22,30]amongothers),com-parativelylittleworkhasbeendoneonrigorous,language-basedapproachestotransactions.Therearemanyopenquestionsandchallenges:WhichstandardACID(Atom-
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PPDP’05,July11–13,2005,Lisbon,Portugal.
Copyright2005ACM1-/05/0007...$5.00.
icity,Consistency,Isolation,andDurability)propertiesoftransactionsareactuallyusefulforcommonconcurrentpro-gramming?Howshouldtheenforcementofthesepropertiesbeefficientlyimplemented?Whatnewlanguagefeaturesarerequired,e.g.forperforminginput/output(I/O).Howmuchinformationcanbeverifiedstaticallyinordertodecreasetheruntimesupportnecessaryforrunningtransactions?
Weconsidertheaboveissuesinthecontextofnetworkedapplications,whichareinherentlyconcurrent.AdistinctfeatureoftheseapplicationsisthattheyperformmanyI/Ooperationssuchassendingandrecetheyalsodemandahighlevelofrobustnessandefficiency,withpossibletimelinessconstraints.
Inthepast,suchsystemswereconfinedmostlytodomainsliketelecommunicationsswitches,flightreservationsandairtrafficcontrol.However,todaymoreandmoresystemshavesimilarrequirements,includingconsumerelectronics,andmobileembeddedsystems.Transactionsmaygreatlysim-plifytheirdevelopment.Unfortunately,traditionaltransac-tiontechniquescanseldombetransferredfromthedatabasetotime-criticatheperformanceconsiderationsaretoodifferent[29,13,3].
Thispaperdescribesalanguageandruntimesupportforisolation-only,localtransactions,calledtasks.Theisolationproperty[32](alsoknownasserializability)ensuresthattheconcurrentexecutionoftasksisequivalenttoanexecutioninwhichthetasksareserialized.Tasksallowisolationtobedeclaredinsteadofhavingtobeencodedusingthelow-levelsynchronizationmeans.
Contrarytosimilarconstructsfordeclaringatomicblocksthatwedescribein§6,ourtaskscanperformarbitraryop-erations,includingI/O,withtheisolationguarantee.Themainideaistoavoidtheneedforrollbackatruntime(duetoe.g.,conflictsontaskoperations),bytightlycontrollingtheorderofsuchoperationsandguaranteeingthatoncestartedataskcannotrunintoconflicts.Noexplicitrollbackbytheprogramisallowed.
Theisolationguaranteeinourlanguagestemsfromthreesources:
ocompiletimeenforcementthateachshareddataloca-tion(oranI/Ooperation)isprotectedbyalockandthatthreadsacquirethecorrespondinglockbeforeac-cessingthelocation(orperformingtheI/Ooperation);thisisbasedonpreviousworkofAbadiandFlanaganontypesforsafelocking[9],ocompiletimeenforcementthatrequiresthatalllockstobeacquiredduringataskaredeclaredatthebegin-ningofthetask,
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喜欢此文档的还喜欢dynamic typing
动态类型（Dynamic Typing）就是指，对象实际使用的是哪一个类是在执行期间确定的，而非在编译期间。
基于29个网页-
动态定型 (dynamic typing): 不需要宣告变数型态
用内缩表示回圈和其他的阶层
基于4个网页-
动态型别（Dynamic Typing）是好的，因为你不需要预先限制特定资料呈现。但我认为，灵活性的关键在于让程式语言更为抽象。
基于4个网页-
动态类型语言
静态类型与动态类型
优雅语法和动态类型
更多收起网络短语
- 引用次数：1
参考来源 -
&2,447,543篇论文数据，部分数据来源于NoteExpress
In cases where dynamic typing is more convenient, the Dynamic type can be used, enabling arbitrary access to properties and methods on Dynamic variables.
有些情况下，动态类型更方便，我们可以使用Dynamic类型，从而可以对Dynamic变量的属性和方法进行任意地访问。
In addition to the three characteristics cited in the quote, single inheritance and dynamic typing were often cited as "absolute requirements" to be an OO language.
除了之前提到的三个特征，单继承和动态类型也被引用为面向对象语言的“绝对需求”。
You probably recognize the dynamic typing model, functional programming in the form of higher-order functions, and an open object model as ideas I've presented in other Crossing borders articles.
您可能已经熟悉动态类型模型、高阶函数形式的函数式编程以及开放对象模型这些概念，因为我在其他的跨越边界 系列文章中已经作过相关的介绍。
点击关注有道词典
$firstVoiceSent
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请问您想要如何调整此模块？
感谢您的反馈，我们会尽快进行适当修改！
请问您想要如何调整此模块？
感谢您的反馈，我们会尽快进行适当修改！请大家帮我看看这句话中in typing是什么意思I still decided to take a course in typing given by the government这句话中in typing
任性的公猫176
打字.take a course就是"选读什么课"/"上什么课".in是一个介词,后面的名词只能用名词或动名词,因为type是动词,所以用了typing.比如说,I took a course in English.这句话的意思是“我选读了英语课”.
为您推荐：
其他类似问题
打字我还是决定去上那个政府开的打字班
in type [简明英汉词典]排好版
扫描下载二维码小题1:hungry&&&小题2:was waiting&小题3:asleep&&&小题4:firemen&&&小题5:spread小题6:kitchen&&小题7:luckily&&&&&&小题8:filled&&&小题9:while&&&&小题10:unconscious 小题1:对应下文的eat。小题2:边看电视边等待。两个动作同时进行。小题3:fall asleep入睡。小题4:与下文的caught fire呼应。小题5:flames火焰传播spread。小题6:结合the fire had spread from the kitchen into the living room可知答案。小题7:自家厨房失火，邻居报警，自然是幸运的。注意此处修饰整个句子，要用副词。小题8:be filled with充满。小题9:有句子结构判断此处需要连词。 小题10:消防员发现作者时，作者已经失去知觉了。
请在这里输入关键词：
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题型：听力题
单词拼写（共10小题，每小题1.5分，满分15分）小题1:This medicine will ___________ （治愈）you of your headache.小题2:Don’t ___________ （暴露）yourself to the sun too long.小题3:There are two new houses under ___________（建设）小题4:He was ____________ （不愿意）to pay the fine.小题5:To our ___________（高兴）our football team won.小题6:These gates are always open for the ____________（方便） of visitors.小题7:At the meeting ，he would __________ （阐明）his own views.小题8:You can discover many types of wildlife in the ___________ （环境）of a traditional farm.小题9:He looked at the gold with ____________（贪婪的）eyes.小题10:Remember to put the waste into the ___________.（垃圾桶）
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完成句子（共6小题；每小题1分，满分6分）小题1:He ________ _________ ______ people who’ve never been to university. (瞧不起)小题2:I __________ him ______ her honesty. (使….确信)小题3:They need more troops to _________ the border _________ possible attack. (保卫…以免受)小题4:The police _________ _________ _______________ that he was the criminal of the murder. (得出结论)小题5:Do remember to remind me of the meeting because I _______ ________ ________ forget it. (很可能)小题6:The sentence just doesn’t ________ ________ no matter how you read it. (讲得通；有意义)
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根据下列句子所给汉语意思，写出空缺处各单词的正确形式。小题1:______(旅游业) is a big business for small countries like Singapore.小题2:We measured the _______(长度)and width of the living room.小题3:I cautiously ________(走近) the house only to find that nobody was there.小题4:It was _______(体贴的) of you not to play the piano while I was asleep.小题5:The house was painted green_______(到处).
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题型：听力题
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科目：高中英语
来源：不详
题型：听力题
单词拼写小题1:She__________(提醒)me that I hadn’t written to Mother．小题2:The medicine has no side________(效果)on you?小题3:The actor owes his success to his_________(父母)．小题4:On graduation day，Frank and I were________(出席)at the ceremony .小题5:Much to my surprise, the flowers are still in bloom in _______ (六月)．小题6:In the __________(二十)century，country music became more popular .小题7:Your duties__________(包括)typing and answering the telephone．小题8:His words are strongly___________(留下印象)on my memory．小题9:More efforts and you’ll surely__________(成功) in this field.小题10:It’s good ________(礼貌) to behave yourself well.
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