MIT Incremental Propagation

[John Hascall]

> >Ubik is an elected-master protocol.  All updates go to the master
> >which replicates.  If the master goes away, after a while the
> >remaining nodes notice and revote a new master (this can take a while).
> >
> >I'm not sure that model works well with the KDC's single-threadedness.
> >
> >I expect a 3-phase commit model would be more robust.
> 
> I think you're conflating the master election protocol with the
> transaction protocol.  You still need to decide on a master (aka
> "coordinator") with 2PC or 3PC.

   You do not.  Each transaction can be mastered by whichever
   node it starts out on.  As soon as it has >50% acks to the
   prepare, it can issue the commits.  At the same time another
   node can be mastering a different transaction.

John