kc第講并發(fā)控制技術(shù)

第17講:(第16章)

并發(fā)控制技術(shù)

重慶大學(xué)計算機學(xué)院課程名稱:數(shù)據(jù)庫系統(tǒng)

--------------------第17講:并發(fā)控制技術(shù)項目驅(qū)動目標：

關(guān)系數(shù)據(jù)庫如何實現(xiàn)對多個應(yīng)用并發(fā)訪問的控制：一、基于鎖的協(xié)議 二、多粒度 三、死鎖處理 四、基于時間戳的協(xié)議 主要討論問題：什么是鎖，有哪些基本類型？什么叫死鎖？什么是兩階段封鎖協(xié)議？除X,S鎖外,還有其它類型的鎖？意向鎖的相容關(guān)系如何？如何檢測是否存在死鎖？什么是時間戳協(xié)議？時間戳協(xié)議為何能保持可串行化？Exercise17LocksandItstypesAlockisamechanismtocontrolconcurrentaccesstoadataitemDataitemscanbelockedintwomodes:排它鎖exclusive(X)mode.Dataitemcanbebothreadaswellaswritten.X-lockisrequestedusinglock-Xinstruction.共享鎖shared(S)mode.Dataitemcanonlyberead.S-lockisrequestedusinglock-Sinstruction.Lockrequestsaremadetoconcurrency-controlmanager.Transactioncanproceed繼續(xù)進行

onlyafterrequestisgranted.一基于鎖的協(xié)議1-1什么是鎖，有哪些基本類型？1.1鎖Lock-compatibility相容矩陣：Lock-compatibilitymatrix作用：AtransactionmaybegrantedalockonanitemiftherequestedlockiscompatiblewithlocksalreadyheldontheitembyothertransactionsAnynumberoftransactionscanholdsharedlocksonanitem,butifanytransactionholdsanexclusiveontheitemnoothertransactionmayholdanylockontheitem.Ifalockcannotbegranted,therequestingtransactionismadetowaittillallincompatiblelocksheldbyothertransactionshavebeenreleased.Thelockisthengranted.直觀例示(例子)1-2什么是鎖的相容性？1.1鎖ExampleofUsingLocksExampleofatransactionperforminglocking:

T2:lock-S(A);read(A);unlock(A);lock-S(B);read(B);unlock(B);display(A+B)Lockingasaboveisnotsufficienttoguaranteeserializability,ifAandBgetupdated(bysomeothertransactionT1:轉(zhuǎn)賬50)in-betweenthereadsofAandB,thedisplayedsumwouldbewrong.Alockingprotocolisasetofrulesfollowedbyalltransactionswhilerequestingandreleasinglocks.Lockingprotocolsrestrict限制

thesetofpossibleschedules.1-3什么是封鎖協(xié)議？T1:lock-X(B);read(B);B:=B-50;write(B);unlock(B);Lock-X(A)read(A)A:=A+50write(A)unlock(A)若：Ais100Bis200則該調(diào)度后T2顯示：A+B=150------------而T1,T2后T2顯示300而T2,T1后T2顯示300(原因分析)1.1鎖Pitfalls陷阱ofLock-BasedProtocols-死鎖Considerthepartialschedule

Neither

T3

nor

T4canmakeprogress—executinglock-S(B)causesT4towaitforT3toreleaseitslockonB,whileexecutinglock-X(A)causesT3

towaitforT4toreleaseitslockonA.Suchasituationiscalledadeadlock.死鎖，問題如何解決？TohandleadeadlockoneofT3orT4mustberolledbackand

itslocksreleased.1-4什么叫死鎖？1.2死鎖與活鎖PitfallsofLock-BasedProtocols-活鎖Thepotential潛在的

fordeadlockexistsinmostlockingprotocols.Deadlocksareanecessaryevil不可避免的惡魔.Starvation

饑餓/餓死

isalsopossibleifconcurrencycontrolmanagerisbadlydesigned.Forexample:AtransactionmaybewaitingforanX-lockonanitem,whileasequenceofothertransactionsrequestandaregrantedanS-lockonthesameitem.Thesametransactionisrepeatedlyrolledbackduetodeadlocks.Concurrencycontrolmanagercanbedesignedtopreventstarvation.

(如何解決?)當(dāng)事務(wù)T申請對數(shù)據(jù)項Q加M型鎖時：當(dāng)前不存在已對數(shù)據(jù)項Q持有與M沖突的鎖的其他事務(wù)當(dāng)前不存在(先于T申請)正等待對數(shù)據(jù)項Q加鎖的其他事務(wù)1-5什么叫活鎖(餓死)？1.2死鎖與活鎖TheTwo-PhaseLockingProtocolThisisaprotocolwhichensuresconflict-serializableschedules.第1階段Phase1:增長GrowingPhasetransactionmayobtainlocks,but

加鎖階段！transactionmaynotreleaselocks第2階段Phase2:縮減ShrinkingPhasetransactionmayreleaselocks,but釋放鎖階段！transactionmaynotobtainlocks例子(p.421圖16-5和16-6中的T3和T4都是兩階段的p.420圖16-2和16-3中的T1和T2都不是兩階段的)Theprotocolassuresserializability.Itcanbeprovedthatthetransactionscanbeserializedintheorderoftheirlockpoints

(i.e.thepointwhereatransactionacquireditsfinallock)(留作練習(xí),習(xí)題16.1).1.3兩階段封鎖協(xié)議1-6什么是兩階段封鎖協(xié)議？Strict&RigorousTwo-PhaseLockingProtocolTwo-phaselockingdoesnotensurefreedomfromdeadlocks(圖16-7調(diào)度2)Cascadingroll-backispossibleundertwo-phaselocking.

(圖16-8,T5撤銷時T6,T7撤銷)Toavoidthis,followamodifiedprotocolcalledstricttwo-phaselocking.Hereatransactionmustholdallitsexclusivelockstillitcommits/aborts.Rigoroustwo-phaselockingisevenstricter:hereall

locksareheldtillcommit/abort.Inthisprotocoltransactionscanbeserializedintheorderinwhichtheycommit.說明：大部分數(shù)據(jù)庫系統(tǒng)都采用這兩種封鎖協(xié)議之一！p.422圖16-8部分調(diào)度1-7什么是嚴格兩階段封鎖協(xié)議？1-8什么是強兩階段封鎖協(xié)議？1.3兩階段封鎖協(xié)議Im易pl陪em虜en透ta援ti喝on籠o巾f波Lo塘ck撒in丸gAlo插ck今m奇an徒ag傘erca插n稻be漿i灑mp黨le梢me陳nt拘ed標a束s胳ase皺pa演ra揪tepr受oc系es戰(zhàn)s得to像w魚hi恨ch屠t梢ra識ns歌ac或ti妙on蛙s悲se每nd濱l孕oc穩(wěn)k由an征d儀un垮lo談ck受r堆eq旋ue芬st桃sTh粒e啦lo哪ck大m壟an頃ag忘erre攏pl步ie押sto故a份l鞋oc擋k悉re辮qu機es周t膝by治s盈en齡di近ng弓a呼l窗oc綁k糟gr鈴an救t糖me柜ss擊ag革es磁(弦or謹a及m既es機sa椒ge沒a乖sk敢in臘g揀th小e事tr牲an斗sa鉤ct帽io以n拌to嬸r乖ol訂l惑ba發(fā)ck秤,悅in捉c脹as下e園of扛a犯de侵ad音lo陸ck兄)Th斗e仍re陰qu著es御ti施ng魯t伙ra尤ns劃ac可ti捎onwa仇it維sun召ti拾l(fā)夜it蓋s雨re況qu靈es振t誘is健a蝴ns部we退re心dTh抵e獄lo與ck魯m偉an山ag怎er牢m踐ai香nt啦ai祥ns希a常d哥at怒a-憲st紐奉ru謝ct中ur傍e鄉(xiāng)豐ca果ll溪ed昨alo陸ck伏t匯ab些leto盟r煎ec跌or證d泉gr株an孕te染d冬lo鵲ck楊s拖an蚊d正pe幻玉nd詢in貝g犁re借qu怎es壤tsTh喂e冰lo任ck杰t軟ab販le吃i廟s腹us的ua成ll西y淚im罩pl易em等en橋te鳳d啞as花a賞nin視-m饒em孝or也y精ha泊sh醫(yī)t炊ab粥l(xiāng)ein戰(zhàn)de慎xe肺d員on衣t撤he丘n素am景e拘of養(yǎng)t傅he免d燭at鞭a燦it著em啄b乎ei取nglo紐奉ck乎edlo先ck便t貍ab寧le1.售4鎖管仔理器1-絡(luò)9封鎖進管理驗如何辨實現(xiàn)之？Lo石ck屑T逢ab鹽leBl熱ac截kre托ct押an營gl婦es脊i燙nd脂ic競at帳e文gr孩an初te型d腿lo般ck序s,wh欲it籌eon至es井i焰nd晶ic瞎at搜e升wa聞it腦in及g歐re逝qu禁es裙tsLo至ck凳t道ab牌le偽a積ls浴o菌re牽co想rd仍s搭th評ety許pe(圖中書未標創(chuàng)出)oflo左ck際g嚷ra魚nt邁ed進o酸rre獄qu炭es跡te枝dNe擊w蔥re蛾qu公es右t刺isad嫂de乖dto京t秀he素e求nd撿o趴f斜th鍵e罪qu匆eu預(yù)e端of城r吐eq結(jié)ue夫st妄s牢fo課r滿th庫e紛da杏ta孝i忌te衫m(xù),豈a聚ndgr銳an角te糞dif克i襪t獵is銹c總om頓pa茄ti覆bl乞e鍬wi愿th諸a赤l(xiāng)l嶼e繪ar動li揭er想l理oc放ksUn污lo毀ck茅r慶eq照ue蹄st拌s糟re佳su造lt熱i庸n來th霜e禿re塑qu植es鞭t鐮be形in濫gde醉le新te俊d,鍬an重d況la捏te銀r慈re井qu呈es劍ts貨a行re狐c纖he艇ck導(dǎo)ed漸t翅o村se酸e嘴if其t綁he唉y淋ca蒜n擱no物w器begr兇an炸te副dIf供t觀ra題ns尚ac星ti叫on姨a濕bo餐rt春s,al斑lwa凳it訊in壤g掘or恥g岸ra殘nt按ed適r械eq盒ue油st伍s烤of絞t絲式he思t槍ra找ns伸ac詳ti盟on徑a罩re離d幟el菊et累edlo化ck量m瓶an夜ag爽er擠m宿ayke嘴epa怠li難st旅o阻f晴lo球ck振s除he盒l(wèi)d忠b裂y值ea律ch遮t譯ra牢ns溉ac攤ti花on杜,賴to蠢i統(tǒng)mp快le蹈me吹nt遞t香hi工s幫ef懼fi時ci找en泰tl鼠y數(shù)據(jù)項的hash鏈表當(dāng)前有五個數(shù)據(jù)項:I7,I23,I192,I4,I44有相同hash的數(shù)據(jù)項GrantedWaiting1-嗽10什么示是鎖伯表,有何悟用途打？1.京4鎖管鐘理器Mu食lt蔽ip盞leGr庫an芳ulari哥ty粒度Al蛾lo末w杰d慰at輛a火it狹em英s溫to我b犬e垮ofva區(qū)ri玻ou漲s寄si施ze皺san合d依de昌fi鄙ne惜a護h特ie去ra贈rc游hy沫o炒f某da巴ta醉g綁ra拖nu鍋la牌ri委ti掏es凳,扣wh淺er柿e蠟th虜e繡sm皇al胳l浙gr翼an度ul奸ar界it船ie斃s邪ar庫ene滾st默edwi假th蕩in壟l對ar寺ge戲r犧on室esCa朗n委be絲式r猶ep宜re萌se坡nt緒ed押g要ra且ph何ic遠al置ly陰a銀s碧atr裕ee盞(例子)Wh劫en爭a點t紡ra謹ns算ac陜ti牧on坊l唐oc抱ks維a襯n伍od槽e選in仆t塞he芬t任re帽eex膀pl墊ic依it書ly,癢itim混pl悲ic短it趣lylo惕ck位s秘al配l若th錄e國no威de蓮's柱d施es百ce仁nd聞en搖ts潛i攤n眾th觀e儀sa航me強m邁od衰e.Gr凝an價ul閱ar揭it襖y陵of切l(wèi)齡oc逃ki向ng(l屯ev鮮el蓄i春n秩tr秘ee狹w群he非re煮l浩oc擺ki勇ng射i柔s奪do砌ne棒):細粒等度鎖fi躺negr叨an并ul傷ar排it巨y(l庫ow棋er詠i盡n別tr諒ee壞):在h急ig桑h衡co扔nc框ur律re流nc蛾y,草h槽ig賤h鎖lo牧ck臺in擴g口ov妙er弟he私ad粗粒牲度鎖co啊ar腎segr杜an隱ul觀ar梳it篇y(h碧ig狐he掩r鑄in去t鋒re般e)之:匹lo枕w則lo話ck營in突g鄭ov悔er戒he批ad柜,鏡lo渣w叛co毀nc遺ur夏re皺nc尚y二乏多粒大度2.繳1數(shù)據(jù)殊粒度宅與封驗鎖2-經(jīng)1什么室是數(shù)耽據(jù)?；糜穸龋?-響2多粒欣度數(shù)已據(jù)如圍何封詢鎖？Ex錄am千pl團eof虎G毀ra疑nu辟la嚼ri太ty羽H乏ie釘ra圈rc嘉hyTh鎖e防le趕ve休ls倦,煤st眨ar坦ti吃ng勉f薯ro哭m繭th顯e最co雞ar例se姑st鑼(瘦to期p)味l愧ev邪el襲a蔽reDa腥ta梯ba昂seAr糊eaFi責(zé)lere匠co震rd數(shù)據(jù)庫級區(qū)域級文件級記錄級2.型1數(shù)據(jù)榆粒度口與封爪鎖In螞te憲nt他io今nLo倚ck件M纏od坦es例子(意向旗所用避途分撞析)in惕te歲nt虹io對n律lo刊ck寧s概al圣lo尾w錯a說hi匆gh狹er蘋l偽ev垮el始n話od尼e放to戀b糖e哀lo沖ck澆ed免i省nS槳or握Xmo浸dewi咱th乖ou遭tha世vi軟ng俱t祖o解ch桂ec辨k棉al和l注de丈sc棟en世de跨nt多n鞠od棄es倉.Inad齡di崖ti錄on鐮t挑o侮S寄an饅d櫻X睡lo刊ck盯m用od液es耐,授th澆er瘦e粗ar蟻eth姑re鵝ead新di虛ti的on踏al辭l庸oc筐k刪mo偏de免s堂wi絲式th徑m咐ul壤ti村pl棚egr醋an禽ul剝ar腸it像y:in假te買nt憤io谷n-赴sh附ar潮ed(I托S)共享己意向暢鎖:in導(dǎo)di父ca偽te蘆s征ex草pl士ic扎it捏l疫oc黨ki撈ng變a禁t歷a觸lo薦we概r頌le拉ve很l原of郊t艙he距t劉re盤e漿bu滑t羽on陵ly王w食it怨h壇sh和ar員edlo駛ck枯s.低層叼有顯錢示S鎖in蛇te派nt仙io渠n-ex俊cl累us享iv披e(I愛X)排它千意向攜鎖:in睬di厭ca患te兇s付ex報pl純ic龜it館l脆oc兩ki賺ng隆a堂t狐a燥lo扶we苗r俯le累ve震l詠wi振th覆e閑xc謠lu缸si冰ve咬o認r稼sh瀉ar胸edlo稻ck片s.低層加有顯佛示X/訴S鎖sh炊ar灣ed患a條nd單i況nt注en鋼ti血on-ex詞cl壩us洽iv饅e(S翅IX)共享旨排它邀意向鍛鎖:th苗e棄su潤bt哥re恭e剃ro剃ot乒ed東b摔y掃th聚at坡n勵od驕e企is機l奸oc王ke母d販ex沾pl耐ic戀it革ly灑i休nsh月ar側(cè)edmo反dean唇dex疼pl和ic描it必l肝oc拔ki霜ng子i姐s刃be舌in峰g乖do迷ne與a仰t靈a拜lo第we盜r懷le腥ve現(xiàn)l纏wi驗thex淡cl訂us揪iv艱e-汪mo霉delo命ck購s.意向常鎖相容勝矩陣多粒糟度封鎖具協(xié)議2.厲2意向熟鎖2-掏3除X,圓S鎖外,還有遣其它信類型塑的鎖珠？Gr賀an步ul靜ar削it組yHi襪er扔ar婚ch童y-用途份分析2-評4為何噴需要沸意向暴鎖？2.隆2意向篇鎖之后,顫Tk可以齒對DB加鎖某？需檢生查所局有節(jié)亞點,搜索至整個格樹!解決趨辦法捎：Ti可對Fc加顯江示鎖糞時，錢同時對到狀根路府徑的抖所有革父節(jié)推點加秩意向芒鎖！然后盜利用多粒沙度封口鎖協(xié)構(gòu)議判斷家是否傅可加化鎖！假設(shè)：Ti已對Fc加鎖Ti已同時對DB和A2加意向鎖！Co瓦mp罰at怎ib喂il禿it剛y音Ma此tr唉ix遍w權(quán)it謎h姜I績nt廳en饑ti象on燃L紹oc簡k塑Mo拘de副sTh累e惠co液mp耀at耀ib狂il曲it療y稼ma皆tr越ix魔f免or懶a辦ll蛛l碰oc上k閥mo淡de坊s籌is俊:ISIXSSIXXISIXSSIXX2-釋5意向討鎖的束相容蓋關(guān)系聰如何粘？2.許2意向吃鎖Mu佳lt獲ip徐le垮G紙ra疾nu反la倒ri夾ty虧L射oc怖ki狡ng慣S歐ch遮em濃e多粒敘封度美鎖協(xié)港議:T英ra均ns妻ac儀ti博onTica途n致lo暖ck斗a哪n藥od惜eQ,忌us煮in邁g領(lǐng)th笑e叮fo遮ll猜ow摟in謊g餓ru趕le賢s:Th唯e抹lo云ck徒c橋om勿pa捏ti無bi卸li捏ty賺m舞at周ri渣x魚mu躲st夠b長e廚ob尾se賺rv閃ed肉.Th特e后ro啟ot要o叫f忠th蔥e鬧tr擴ee及m岸us露t市be惑l奏oc跪ke道d訊fi中rs停t,起a榜nd廊m悟ay疲b紗e序lo里ck鳴ed瞇i前n轉(zhuǎn)an蛛y研mo掛de裂.A漲no過deQca低n摔be部l弊oc桶ke坡d故byTiin灶S軋o散r諷IS者m宰od輔e貢on泊ly嗚i廚f維th念e悄pa深re挺nt辣o倚fQis升c懼ur坦re饑nt撞ly求l毀oc鑒ke營d藝byTiin閃e洪it土he儀r秩IX座o吊r蹄IS偽m昨od雄e.A睡no慰deQca劇n礎(chǔ)be白l洲oc植ke里d愿byTiin故X檔,懂SI唉X,拖o筑r吧IX爽m鏟od倦e壩on蛙ly洗i紋f切th舅e彎pa承re娘nt刃o蔥fQis季c勞ur郵re惕nt憐ly垂l殲oc里ke稼d解byTiin揮e甘it枯he恰r鐘IX膝o共r就SI脆X助mo助de犁.Tica忽n狀lo劍ck高a核n逆od熔e切on勺ly真i保f態(tài)it梨h藥as志n妻ot村p塵re逝vi撫ou像sl偶y儲un廉lo憂ck豈ed門a禍ny晉n然od套e霞(t姓ha賴t聲is踏,Tiis帥t條wo喘-p勉ha侮se體).Tica臥n饑un仍lo牙ck蠟a暗n過od績eQon悄ly聽i膀f速no竹ne廈o刻f瞎th圖e級ch繩il完dr睬en逗o非fQar塔e遙cu政rr嗓en未tl慰y搶lo信ck陪ed緒b翼yTi.特點攪：Ob槳se蒸rv永eth責(zé)at語l訊oc袖ks貝a拳re購a仙cq籌ui炕re頌d獲得inro幻玉ot去-t王o-巾le密af亭o謙rd徒er添,散wh顧er械ea汗s舅th街ey疫a思re勵r志el量ea澡se陵d鼻in幟l丹ea吊f-館to后-r螺oo怖t嶼or帥de岔r.2-扭6什么瘡是多軋粒度番封鎖狀協(xié)議濱？2.昨2意向類鎖De旺ad秩lo星ck-例子Co螞ns塑id賄er暗t蠻he鐘f華ol給lo濕wi陰ng攏t戴wo默t恥ra吊ns極ac襖ti筋on湖s:T1:徹wr陷it定e毯(X)T2:丹w斤ri樓te泡(Y)wr利it計e(Y)鼻wr聲it殊e(X)Sc哨he瓦du以le靜w乘it礦h哀de臂ad鵲lo協(xié)ckT1T2lock-XonXwrite(X)lock-XonYwrite(Y)waitforlock-XonXwaitforlock-XonY三片死鎖鋼處理3.杜1死鎖3-逮1何時茫會出風(fēng)現(xiàn)死萄鎖？De涼ad渠lo市ck索H票an爽dl眼in誤gSy附st顆em天i擁sde考ad嫩lo淘ck俊edifth聯(lián)er掀e芽is柜a兔s球et鹿o奪f遞tr繼an阻sa蜻ct究io泊ns搖s訊uc綢h痛th長atev膚er杰ytr纏an鋸sa猛ct儲io彩n扁in己t董h(huán)e慨s患et謊i流s唇wa投it炸in班g呈fo晴r普an畏ot次he峰r敗tr伍an涼sa都ct奇io就n嗽in深t艦he喚s很et仇.De警ad河lo燃ck敬p芽re概ve蛙nt糧io刃npr險ot踏oc嗎ol粥sen計su陽re世t科ha宰t征th各e歷sy豈st悉em凍w蠶il對lne毯ve盈ren溜te榜r炕in杏to齡a冶d爽ea腸dl植oc傲k幟st鴿at慌e.So盛mepr蠢ev剃en蹄ti刺on賞s料tr微at郵eg薄ie貓s凱:法1：Re延qu胃ir況eth艙at炕e搶ac拉h(huán)蘆tr吸an遺sa舌ct僵io尋n保lo傍ck狂sal拖lit葡s巖da菠ta亞i扎te藏ms宵b浸ef口or鍛e觸it型b擾eg窗in你s堵ex坐ec伴ut旅io喊n虹(p裕re傅de孫cl跡ar找at捐io交n).預(yù)先度聲明法2：Im何po總se強制pa約rt獅ia液l痛or是de在ri己ng宋o塵fal琴lda劣ta犁i禽te帝msan淹dre洲qu環(huán)ir筒e銜th嘆at銳a虧t澡ra憂ns逮ac浙ti霸on海c羞an昨l烘oc范k呼da夫ta赤i籍te旋ms匹o燙nl內(nèi)yin遇t弟he伐o掘rd墻ersp滲ec杠if蠟ie晚d相by顧t樸he顯p依ar取ti蓬al坐o貸rd逗er控(柜gr蠅ap園h-什ba伙se襖d斷pr性ot美oc饒ol).基于拖圖的搞協(xié)議(p浸.4婆24槐)3.沈2死鎖興預(yù)防3-覽2如何物預(yù)防氏死鎖琴？Mo拾re給D嚼ea洗dl播oc繼k悼Pr克ev悲en弟ti消on歌S徹tr倒at旱eg幼ie并sFo涼ll統(tǒng)ow蘇in抵g臭sc疤he烤me弊s味us傘e盡tr匯an顫sa尾ct轉(zhuǎn)io輩nti蟻me蕉st匙am擔(dān)ps時間屬戳fo匙r習(xí)th珠e子sa潤ke研o瘡f繼de伸ad這lo誼ck乒p番re撕ve炕nt洽io疤n申al勇on須e.法1）wa轎it傳-d綢iesc移he屋me扶—no記n-或pr稱ee區(qū)mp秘ti狠ve非搶淘占式ol不de源r爺tr壓an男sa浸ct公io陜n方ma妖ywa修itfo涌r本yo貫un正ge段r蘿on辱e踏to醒r濫el墾ea醒se爭d檔at證a斧it滴em裂.Yo疾un攪ge原r切tr卻an懷sa棄ct約io扭ns膨n蝴ev摸er袖w孟ai除tfo范r紀ol學(xué)de思ron堵es尚(灑th番eyar膜e濃ro呢ll把ed啞b鞏ac殃kin久st糧ea誼d)現(xiàn).范(有沖認突時億，新豎的事算物自圍動回宏卷)a眾tr墾an慌sa傍ct材io縫n薪ma衫y貪di泛ese雕ve棉r(nóng)a明lti禽me唐s火be氏fo顏re夠a題cq輛ui火ri省ng斃n遲ee猜de柜d風(fēng)da諷ta流i層te球m法2）wo觀un舅d-喪wa平itsc狗he明me墨—pr威ee傻mp沖ti燙ve搶占紛式ol郊de犬r疑tr溝an凱sa甜ct逆io訴nwo炸un哨ds(f貓or避ce壩s晝ro低ll柔ba噸ck圣)紋of掀y琴ou貓ng拖er等t桶ra著ns彩ac攤ti側(cè)on碼i煉ns殃te宏ad布o低f碰wa孤it侄in災(zāi)g耐fo搬r瞞it揭.Yo誓un騙ge手r晝tr梨an次sa廈ct兩io爹ns悔m席ay狠w瞧ai宏tfo昌r伶ol歲de伙ron滑es勇.薄(有沖港突時胸，老銜的事旋物強孕制將戒新的醋事物污回卷)ma宴y丈befe爽we蛇rro該ll仆ba蹦ck立s家th炸anwa愛it份-d最iesc持he餅me錯.法3）（待續(xù)…）3-匆3還有拐其他怕預(yù)防店死鎖厘方法襲？3.誤2死鎖尖預(yù)防說明崖：Bo乳thinwa稿it允-d買iean單d頃inwo巡壽un壩d-槽wa漿itsc走he郊me榨s,脈a句r卡ol爺le合d旗ba閑ck嫂t達ra斗ns經(jīng)ac鋸ti米on銀s嫩is凈r慣es花ta燃rt深ed記w匪it乒h負it貢s堆or鵝ig委in側(cè)al練t畢im頁es潔ta天mp粒.她Ol缺de姜r非tr岔an裹sa汁ct俘io選ns籮t根hu繡s皆ha剖ve騎p純re手ce極de燭nc智e慢ov漫er溜n震ew峽er亞o嘉ne胃s,懸a摔ndst癥ar斤va察ti爸on活鎖is屆h嗎en聰ce什a孤vo曬id湯ed片.法3）Ti始me嘩ou濟t-諒Ba醬se技dSc禁he煙me識s:a夜tr組an產(chǎn)sa際ct灘io草n重wa鼠it秤s卵fo菌r鍛a莊lo輝ck精o鳴nl習(xí)y林fo元ra喘sp痰ec重if貧ie地d績am案ou號nt韻o隱f滴ti歷me.名Af功te們r厘th政at子,豬th建e歸wa午it歪t(yī)旬im就es郊o她ut宰a救nd段t奧he慕t圓ra敏ns扇ac莊ti覺on賄i艇s仿ro朵ll敲ed嘗b私ac攪k.th脊us賢d治ea購dl悔oc館ks連a胸re狡n產(chǎn)ot玩p捏os蛛si座bl谷esi汁mp瞞le熔t望o德im釘pl餓em柴en灰t;泊b赤ut暗s卸ta釀rv街at焰io榨n在is盤p彈os沖si胳bl若e.啊A案ls柔o墊di出ff榜ic塌ul向t陸to周d命et鄰er甚mi拐ne辯g每oo幫d餐va舅lu顏e追of毯t薪he頁t撞im唐eo烏ut榆i薄nt希er暫va丘l.Mo文re跳D微ea篩dl搖oc屋k炸Pr日ev不en宴ti枝onSt挑ra親te酬gi現(xiàn)es(續(xù))3.齡2死鎖掩預(yù)防De粒ad榴lo援ck剛D最et踐ec廁ti冶on等待碎圖：De斗ad裹lo歸ck爸sca油n奶be娛d攏es君cr許ib快ed盲a雅s發(fā)awa雨it疏-f耍orgr甲ap續(xù)h,wh凡ic憂h紫co陡ns炊is影ts廁o脾f頸a真pa只irG=爛(V,E),he著reVis遍a翻s色et綠o查f斬ve壯rt還ic貝es書(醋al脾l釀th也e困tr朽an誼sa毯ct伍io梨ns修i用n臭th模e基sy熊st宰em丟)Eis碎a尖s派et策o咸f治ed顏ge妖s;禮e皆ac甚h籃el戲em察en錘t壟is涌a旅n側(cè)or差de澇re工d南pa綢irTiTj.等待偏圖的偉形成息與更略新：IfTiTjis進i些nE,握th科en襪t扒he轟re崗i讓s純a鍬di逮re劍ct成ed腔e命dg貢e骨fr左omTitoTj,彩im乘pl古yi底ng底t棋ha扎tTiis滿w蜘ai隸ti少ng詳f歉orTjto違r壘el頌ea團se拌a叨d不at艱a察it脫em嗓.Wh揭enTire迎qu擺es失ts沈a眨d畢at燃a艱it柄em鐵c亡ur霜re哭nt塊ly建b設(shè)ei漿ng尼h先el壘d軟byTj,元th新en泥t免he獨e直dg止eTiTjis舌i蕩ns封er稿te折d播in聞t面he壁w嫌ai忘t-潛fo血r顯gr說ap添h.鴿T涂hi打s岸ed旺ge謙i濃s忌re舅mo榨ve顆d秩on紋ly廳w幻玉he恩nTjis折n雜o盆lo前ng池er禿h紐奉ol敗di爆ng柿a趴d暢at那a捏it樓em該n及ee遣de湯d炕byTi.死鎖拖檢測雷方法脫：Th勒esy膠st話em贈i梅s白in獸a福d軍ea柿dl望oc袖k秒st邪at雖eif斧a承nd披o稱nl徒y(tǒng)董ifth吵e企wa票it熊-f周or粒g幼ra負ph后h辦as腳a壁c漏yc須le眨.寒M勝us敢t認in圍vo鍬ke褲a素d形ea散dl猶oc造k-此de慨te遼ct教io航n帽al佳go啦ri包th朽m仆pe蹦ri排od撫ic擋al欄ly偶t伸o棚lo檔ok握f基orcy攏cl沿es擠.等待擺圖示例3.肺3死鎖茂檢測3-屋4如何取檢測騙是否端存在此死鎖午？De技ad死lo繁ckDe歷te傅ct迫io械n-等待挪圖例允子Wa鉛it舒-f駁or綿g辣ra以ph救w拍it媽ho弱ut牢acy狗cl競e不存筆在死睬鎖Wa喬it測-f般or薦g湊ra膏ph博w暴it雞h絹acy工cl商e存在診死鎖解釋燃：3-陣6下兩廉等待車圖存息在死表鎖？3.帥3死鎖圾檢測De龍ad播lo袖ck籌R斷ec昨ov宿er難yWh嬸ende乘ad冬lo絞ck虜i吸s論d早et郊ec速te亂d編:So小me鎮(zhèn)t成ra肅ns洪ac籍ti吩on好w遲il梳l蠢ha鋪ve唱t纖o潛ro坑ll忍ed番b爭ac承k杠(m雷ad蝕e球a州vi巴ct竊im益)陷to苗b仰re退ak液d必ea謠dl表oc渡k.尿Se油le藥ct旱t饑ha蕉t瘦tr杯an俯sa蘋ct筋io庸n告asvict孝im犧牲討品th售at祖w勇il熄l次in歪cu寸rmi狗ni宅mu龜mco楊st(選擇狂事務(wù)浴回卷戀的代川價最優(yōu)小者).Ro壯ll找ba紡ck秘-偏-拾de毯te丘rm摔in艇e慮ho浮w防fa驅(qū)r浙to怨r朽ol勾l熟ba棒ck他t塵ra臣ns爬ac信ti侮on回卷短整個嬸事務(wù)兇：To抖ta矛lro堆ll訪ba雞ck:凡Ab鐵or點t糞th情e過tr強an股sa鋒ct土io濱n頭an燃d賀th尚en遭r琴es癢ta功rt閑i鄰t.回卷慶事務(wù)減的部惡分操角作：Mo慢reef藥fe滔ct芳iv其e糠to榴r爭ol遭l總ba權(quán)ck辯t尿ra摟ns林ac矮ti蜜on傭o芳nl甩y堂as跟f犯ar濃a拼s御ne激ce尸ss桂ar院y就to遍b農(nóng)re通akde千ad縮慧lo召ck.(這種疼情形消要求炭記錄璃運行斜事務(wù)液的相飯關(guān)狀旦態(tài)信嚇息)St梳ar扔va鞠ti占on活鎖ha釣pp振en沒s濃if蔽s贈am蘆e腳tr廁an且sa腫ct臺io忙n柔is卻a敏lw頃ay惜s奪ch減os病en拘a困s循vi養(yǎng)ct獨im雨.(解決攜方法)Bu批t適we池c膜an柏i寬nc變lu竭deth爛e蹲nu混mb井er礎(chǔ)o帖f躲ro卷ll撐ba治ck懲s喝in晶t尋he當(dāng)c際os榴t箭fa練ct責(zé)or當(dāng)t覆o收av犁oi錢d房誠st逗ar窮va乒ti柴on3-瓶7存在偽死鎖撤時如擋何解嘆除？3.菌3死鎖裹檢測Ti嫂me配st取am建p-佳Ba妥se茄d遮Pr丈ot昆oc急ol璃sEa喜ch緩t懲ra兆ns猶ac喬ti疾on踢i扁s許is翠su詳ed演ati童me綿st拜am轎pwh她en麻i篇t誕en畜te哭r(nóng)s株t尤he毛s抬ys佛te申m.禍I依f蹦an密o急ld肺t伍ra鼓ns元ac圣ti浪onTiha含s果ti虧me旬-s點ta煉mp芽T協(xié)S(Ti),音a步n痰ew慌t惠ra暫ns近ac屠ti霞onTjis傷a趨ss洲ig正ne璃d句ti濁me影-s點ta壩mp牌T酷S(Tj)艷su杜ch濾t焦ha沉t候TS臥(Ti)處<T素S(Tj).(利用蘇統(tǒng)一跌的系域統(tǒng)時熱間)Th證e毅pr次ot值oc炭ol奏m綢an瀉ag蒜es捕c真on訴cu啦rr鮮en皇t偶ex鍋ec漆ut穿io獅n熟su攪ch蠻t闖ha鵲t蟲th奴e悶ti倘me免-s租ta貨mp呼sde灣te熱rm失in團eth饑e摩se懸ri榜al襲iz螺ab哲il卷it走y專or頁de鋸r.In桃o缸rd糟er泉t馬o支as掛su扯re磁s射uc姨h醋be住ha番vi麗or衰,淘th步e奮pr咐ot膝oc孕ol綠m塑ai掃nt倦ai詢ns捧f據(jù)orea偉chda巾taQtw鐵oti鞏me維st濃am鹿p孤va河lu削es炸:W-稍ti料me回st丘am冷p(Q)倘is占t傘hela頂rg赴es盜tti車me昌-s吸ta螺mp眠o吵f虜an漠y逢tr蔽an感sa韻ct家io境n雷th尖at陸e餅xe新cu競te介dwr盤it絲式e(Q)思su炊cc碑es戶sf紀ul武ly瘋.R-郊ti航me厭st騾am逗p(Q)窮is飼t脖hela平rg刮es膊tti壇me論-s傾ta甜mp需o司f押an梨y吃tr緒an擾sa尿ct詞io蹦n趨th民at從e郵xe奴cu睬te拒dre娘ad(Q)球su羞cc鞠es挪sf短ul極ly叨.四攜基于傾時間咐戳的衡協(xié)議4-當(dāng)1什么轎是時惜間戳段協(xié)議呆？4.鄙1數(shù)據(jù)松項的羊時間船戳Ti報me謊st痛am搬p-數(shù)Ba瞞se昂d宗Pr宜ot茂oc墳ol鄭s-規(guī)則愿說明Th咱e玩ti甲me拿st皆am綢p綁or厲de柱ri紹ng抽p訓(xùn)ro顛to罷co柳len朽su浮re腎sth道at彎a駛ny篩c鴨on形fl維ic歲ti刊ngre苗adan刊dwr海it取eop仿er男at褲io吹ns只a璃re銷e罪xe貝cu農(nóng)te捧d立in吩t捆im日es招ta竄mp沙o模rd桌er騰.協(xié)議戴規(guī)則暖說明鬼：讀數(shù)碗據(jù)的涉處理:糖Su圈pp妻os顛ea疫tr夾an取sa尤ct益io絡(luò)n挺Tiis顧su矛es配are起ad(Q)1）IfTS岡(Ti)W-t培im嚇es水ta爭mp縱(Q),奧t逝he宇nTine贊ed紀s縱to咽r伴ea微d絮a盒va掏lu攔e皺ofQth胃at喉w褲asal罰re鬼ad詳yov攝er娘wr彎it陳te倉n.老事張務(wù)Ti讀到毅新事芬務(wù)寫由的數(shù)掘據(jù)-異常He恨nc毀e,罷th貸ere哈adop鉗er食at勾io罩n毫isre辜je狐ct來ed,散an筑dTiis侍r丘ol衣le律dba末ck蟲.2）IfTS輕(Ti)W-t奪im盒es激ta五mp承(Q),訪t搶he知n擇th霸ere板adop裕er答at桌io汗n聯(lián)is憲e克xe穗cu限te僵d,an纏dR-波ti爭me憑st費am獵p(Q)isse騎t肆toma伶x(R卡-t畏im降es爪ta培mp某(Q),TS唱(Ti))坦.新事炒務(wù)Ti讀老譯事務(wù)謹寫的惹數(shù)據(jù)-O有K寫數(shù)城據(jù)的處儲理:直觀脫例示吩（例子）4-遲2時間塵戳協(xié)陳議為繁何能惰保持撇可串放行化敬？4.抵2時間月戳協(xié)溜議規(guī)息則Ti端me團st車am秤p-椅Ba宣se龜d廟Pr喜ot路oc櫻ol蒼s-規(guī)則遲說明(續(xù))寫數(shù)窄據(jù)的父處理掛：Su柜pp促os館eth絮at專t們ra點ns忍ac陸ti異onTiis脊su休eswr焰it爬e(Q).1）IfTS墨(Ti)偽<R-t亭im架es堵ta畏mp義(Q),寸t陷he再n陸th梁e昨va售lu蠢e屬ofQth硬atTiis塊p冷ro慢du或ci業(yè)ng顧w章as超n草ee中de構(gòu)d都pr鐵ev壤io循us躬ly宰,技an驅(qū)d幕th輔e圾sy驚st蟻emas西su蓮me市dth征atva嫩lu修ewo塔ul領(lǐng)d碎ne溫ve叢r醉bepr督od箭uc奧ed幅.新事懶務(wù)未矛能讀錄到老氧事務(wù)Ti寫的扭數(shù)據(jù)-異常He懷nc坦e,液t宮hewr奸it排eop章er程at籮io風(fēng)n否isre笨je柿ct菊ed,丘an們dTiis逮r徹ol平le慨d棚ba俊ck鵲.2）IfTS怪(Ti)患<W-t符im厭es裕ta萄mp封(Q),工t挎he輸nTiis旅a偽tt展em程pt判in屠g洽to蛋w雜ri露te糟a境nob困so幫le旨te已過就時的va跑lu餓eofQ.若老面事務(wù)Ti再次憑讀自抹己所撐寫Q,必誤孔讀-異常He爸nc信e,聞t羊hi工s