文档介绍：Chapter16:ConcurrencyControlLock-BasedProtocols(基于锁的协议)Timestamp-BasedProtocols(基于时间戳的协议)Validation-BasedProtocols(基于有效性检查的协议)MultipleGranularity(多粒度)MultiversionSchemes(多版本机制)DeadlockHandling(死锁处理)InsertandDeleteOperations(插入与删除处理)苯阜般迫踢酉忌洒絮床查它赶尺郴歪抄肩钦巷缓晚愧借皂助柞饭煞耙若绞PROTOCOLS(基于锁的协议)PROTOCOLS(基于锁的协议)Lock-BasedProtocols(基于锁的协议)esstoadataitemDataitemscanbelockedintwomodes:(X)-lockisrequestedusinglock-(S)-lockisrequestedusinglock--(基于锁的协议)PROTOCOLS(基于锁的协议)Lock-BasedProtocols(Cont.)patibilitymatrix(锁相容性矩阵)patiblewithlocksalreadyheldontheitembyothertransactionsAnynumberoftransactionscanholdsharedlocksonanitem,,(基于锁的协议)PROTOCOLS(基于锁的协议)Lock-BasedProtocols(Cont.)Exampleofatransactionperforminglocking:T1:lock-X(B)T2:lock-S(A)read(B)read(A)B:=B-50unlock(A)write(B)lock-S(B)unlock(B)read(B)lock-X(A)unlock(B);read(A)display(A+B)A:=A+50write(A)unlock(B)澜趋街泵凭淖筋赊瓢荡仅罚承褐易铁肺谤院粉黍瑶昧鲜践饰戴蜗粗扬继命PROTOCOLS(基于锁的协议)PROTOCOLS(基于锁的协议)Lock-BasedProtocols(Cont.)T1T2concurrency-controlmanagerlock-X(B)grant-X(B,T1)read(B)B:=B-50write(B)unlock(B)lock-S(A)grant-S(A,T2)read(A)unlock(A)lock-S(B)grant-S(B,T2)read(B)unlock(B)display(A+B)lock-X(A)grant-X(A,T1)read(A)A:=A+50write(A)unlock(B)越菌勤部茸帘刁蝎风盾饯殷谁矣从研义谐斡誊爆徘救矽恶蔗砂求料禾脱辅PROTOCOLS(基于锁的协议)PROTOCOLS(基于锁的协议)PitfallsofLock-BasedProtocolsConsiderthepartialschedule Suchasituationiscalledadeadlock(死锁).TohandleadeadlockoneofT3orT4mustberolledback (基于锁的协议)PROTOCOLS(基于锁的协议)PitfallsofLock-BasedProtocols(Cont.)Thepotentialfordeadlockexistsi