DeadlocksLogs & LocksApplicationsTransactionsCentralizedDistributed DataMIT OpenCourseWarehttp://ocw.mit.edu 6.033 Computer System Engineering Spring 2009 For information about citing these materials or our Terms of Use, visit: http://ocw.mit.edu/terms.Recov.: Never modify only copyFailure AtomicityIsolation Æ Serializability LocksTwo-phase lockingDeadlocksread xwrite ycomput’nCOMMIT()acq lxread xacq lyW yacq lyread yacq lxW x1) Timers2) Waits for graphLogs & LocksApplicationsConsistency1) Transactions2) Multi-site atomicityDurabilityTransactionsA C I D PermanenceInvariants must holdCentralizedSID Name DeptID35 ---- 43Integrity rulesDept ID Dept name4325Distributed Data-DNS Æ Expiration time- Web caches“if-modified-since”Strong cons:Read returns result of last write Eventual consistencyMCacheC3C4C2write1) Write-thru cache2) Snoopy
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