Three-phase commit protocol: Difference between revisions

Revision as of 17:32, 5 March 2016

Revision as of 17:41, 7 January 2017

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#The coordinator receives a transaction request. If there is a failure at this point, the coordinator aborts the transaction (i.e. upon recovery, it will consider the transaction aborted). Otherwise, the coordinator sends a canCommit? message to the cohorts and moves to the waiting state.

#If there is a failure, timeout, or if the coordinator receives a No message in the waiting state, the coordinator aborts the transaction and sends an abort message to all cohorts. Otherwise the coordinator will receive Yes messages from all cohorts within the time window, so it sends preCommit messages to all cohorts and moves to the prepared state.

#If the coordinator succeeds in the prepared state, it will move to the commit state. However if the coordinator times out while waiting for an acknowledgement from a cohort, it will abort the transaction. In the case where allan acknowledgementsacknowledgement areis received from the majority of cohorts, the coordinator moves to the commit state as well.

===Cohort===