Talk:Three-phase commit protocol: Difference between revisions

Revision as of 16:54, 18 July 2006

Revision as of 14:28, 7 September 2006

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Regards,

[[User:Igorecan|Igorecan]] 13:14, 11 April 2006 (UTC)

Regarding your comments, Igorecan, I have to disagree. In the situation you mention, in 2PC commit with timeouts, this is how I believe it would go (according to my reading of [http://www.hpl.hp.com/techreports/Compaq-DEC/CRL-93-1.pdf#search=%22a%20new%20presumed%20commit%20protocol%22 Lampson93]):

*Cohort(i) sends an ACK message that gets lost. By the time any cohort can send an ACK, it has already been decided by the coordinator whether the transation is commiting or aborting. So this Cohort is ACKing a commit message in your scenario.

*The Coordinator, knowing that this is a commited transaction, will timeout on Cohort(i)'s response, and will again send a COMMIT message to Cohort(i).

*Cohort(i) upon receiving a COMMIT message for a transaction that has already been commited, will know its ACK message was lost, and will resend the ACK.

*This process might repeat many times until both the COMMIT message and the ACK message were transmited.

Thanks,

[[User:Nbeckman|Nels Beckman]] 14:28, 7 September 2006 (UTC)