[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.
Re: [DISCUSS] CEP 14: Paxos Improvements
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 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
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 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 > 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 >
