This is the presentation I used to give a seminar about the "Paxos Commit" algorithm. It is one of Leslie Lamport's works (in this case, a joint work between him and Jim Gray). You can find the original paper here:
http://research.microsoft.com/users/lamport/pubs/pubs.html#paxos-commit
Feel free to post comments ;)
Enjoy.
Strategies for Landing an Oracle DBA Job as a Fresher
the Paxos Commit algorithm
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6. Paxos Commit (base) Not blocked iff F acceptors respond T 1 T 2 (N=5) (F=2) : Writes on log AC0 L AC1 AC2 RM1 RM2 RM3 RM4 RM0 prepare (N-1) x p2a rm 0 v(rm) (N(F+1)-1) x rm 0 v(rm) rm 0 v(rm) p2b acc rm 0 v(rm) rm 0 v(rm) rm 0 v(rm) Opt. F x If ( Global Commit ) then commit p3 else abort p3 x N 0 0 v(0) p2a 1x BeginCommit
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8. [T 1 ] What if some RMs do not submit their LCV? Leader One majority of acceptors Leader : «Has resource manager j ever proposed you a value?» (Promise not to answer any b L2 <b L1 ) “ accept?” “ promise” “ prepare?” p1a p1b p2a (1) Acceptor i : «Yes, in my last session (ballot) b i with it I accepted its proposal v i » (2) Acceptor i : «No, never» If (at least |MS| acceptors answered) If (for ALL of them case (2) holds) then V=‘a’ [FREE] else V=v(maximum({b i }) [FORCED] Leader : «I am j, I propose V» b L1 >0