Hi Jeremy, That’s a great question, and the answer is that we shouldn’t compare the two as they aren’t in conflict. The goal of this work is only to improve the existing Paxos implementation – the characteristics are identical besides being faster, so this is a simple and safe upgrade route for users in the short to medium term.
Watch this space for a follow up discussion very soon about what we can do to modernise transactions in Cassandra more generally, and what this might mean for how we perform consensus. A comparative discussion of EPaxos and other related work is very well suited to that topic, in my opinion. From: Jeremy Hanna <jeremy.hanna1...@gmail.com> Date: Thursday, 19 August 2021 at 00:58 To: dev@cassandra.apache.org <dev@cassandra.apache.org> Subject: Re: [DISCUSS] CEP 14: Paxos Improvements It sounds like a great improvement! Just for those who had followed the development of ePaxos* that Blake and others worked on but was never committed, it would be nice to briefly compare the two. https://issues.apache.org/jira/browse/CASSANDRA-6246 > On Aug 19, 2021, at 9:18 AM, Scott Andreas <sc...@paradoxica.net> wrote: > > Benedict, thank you for sharing this CEP! > > Adding some notes on why I support this proposal: > > - Reducing common-case round trips from 4x to 2x on writes and 2x to 1x on > reads is a huge improvement. This latency reduction may be sufficient to > allow many users of Cassandra who operate in a single datacenter, > availability zone, or region to migrate to a multi-region topology. > > - The Cluster Simulation work described in CEP-10 provides a toolchain for > probabilistically-exhaustive validation and simulation of transactional > correctness, allowing assertion of linearizability in the presence of > adversarial thread scheduling and message ordering over an unbounded number > of simulated clusters and transactions. > > - Some use cases may see a superlinear increase in LWT performance due to a > reduction in contention afforded by fewer message round-trips. E.g., halving > latency shortens the interval during which competing transactions may > conflict, reducing contention and improving throughput beyond a level that > would be afforded by the latency reduction alone. > > - Better safety among range movements: Electorate verification during range > movements provides a stronger assertion of linearizability via assurance of > the set of instances voting on a transaction. > > – Scott > > ________________________________________ > From: bened...@apache.org <bened...@apache.org> > Sent: Wednesday, August 18, 2021 2:31 PM > To: dev@cassandra.apache.org > Subject: [DISCUSS] CEP 14: Paxos Improvements > > RE: > https://cwiki.apache.org/confluence/display/CASSANDRA/CEP-14%3A+Paxos+Improvements > > I’m proposing this CEP for approval by the project. The goal is to both > improve the performance of LWTs and to ensure their correctness across a > range of scenario like range movements. This work builds upon the Simulator > CEP that has been recently adopted, and patches will follow in the coming > weeks. > > If you have any concerns or questions please raise them here for discussion. > > --------------------------------------------------------------------- > To unsubscribe, e-mail: dev-unsubscr...@cassandra.apache.org > For additional commands, e-mail: dev-h...@cassandra.apache.org >
