Hi Dikang, Have you seen Blake’s work on implementing egalitarian paxos or epaxos*? That might be helpful for the discussion.
Jeremy * https://issues.apache.org/jira/browse/CASSANDRA-6246 > On May 16, 2018, at 3:37 PM, Dikang Gu <dikan...@gmail.com> wrote: > > Hello C* developers, > > I'm working on some performance improvements of the lightweight transitions > (compare and set), I'd like to hear your thoughts about it. > > As you know, current CAS requires 4 round trips to finish, which is not > efficient, especially in cross DC case. > 1) Prepare > 2) Quorum read current value > 3) Propose new value > 4) Commit > > I'm proposing the following improvements to reduce it to 2 round trips, > which is: > 1) Combine prepare and quorum read together, use only one round trip to > decide the ballot and also piggyback the current value in response. > 2) Propose new value, and then send out the commit request asynchronously, > so client will not wait for the ack of the commit. In case of commit > failures, we should still have chance to retry/repair it through hints or > following read/cas events. > > After the improvement, we should be able to finish the CAS operation using > 2 rounds trips. There can be following improvements as well, and this can > be a start point. > > What do you think? Did I miss anything? > > Thanks > Dikang --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@cassandra.apache.org For additional commands, e-mail: dev-h...@cassandra.apache.org
