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Quiz 8_ Distributed Transactions_ 2021F CS 549-A (1).pdf -...

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11/09/2022, 13:11Quiz 8: Distributed Transactions: 2021F CS 549-AQuiz 8: Distributed TransactionsDueNov 1, 2021 at 11:59pmPoints100Questions4AvailableOct 28, 2021 at 8am - Nov 1, 2021 at 11:59pmTime Limit60 MinutesThis quiz is no longer available as the course has been concluded.Attempt HistoryAttemptTimeScoreLATESTAttempt 160 minutes100 out of 100Score for this quiz:100out of 100Submitted Oct 31, 2021 at 5:28pmThis attempt took 60 minutes.30 / 30 ptsQuestion 1Consider the process timeline below, where A is the administrator for2PC. Both A and Z have crashed after the end of the first phase andbefore X and Y can be notified of the administrator's decision.1. Why can't X and Y decide to commit?2. Why can't X and Y decide to abort?
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11/09/2022, 13:11Quiz 8: Distributed Transactions: 2021F CS 549-A2/5take decision on their own and return commit/abort (means they are okor not) to coordinator A. Now before X and Y processes hear about thefinal decision taken by A, A crashed. So now X and Y don't know thedecisions of other processes. And in 2PC it's necessary that all commitor else all abort. So X and Y became orphan and they won't able todecide because it is possible that other process decide to commit but Xdecide to abort and vis versa. Now as coordinator crashed we canchoose any process as coordinator and run whole 2PC again but sinceZ is also crashed we won't able to get consensus and it that case newcoordinator will decide to abort as it won't able to hear back from Z.

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Term
Spring
Professor
N/A
Tags
Database transaction, Coordinator

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