Very exciting! I have a client that's very interested in Accord, so I should have budget to dig into it, especially on the performance side of things.
Jon On Tue, Mar 4, 2025 at 9:57 AM Dmitry Konstantinov <netud...@gmail.com> wrote: > Thank you to all Accord and TCM contributors, it is really exciting to see > a development of such huge and wonderful features moving forward and > opening the door to the new Cassandra epoch! > > On Tue, 4 Mar 2025 at 20:45, Blake Eggleston <bl...@ultrablake.com> wrote: > >> Thanks Benedict! >> >> I’m really excited to see accord reach this milestone, even with these >> caveats. You seem to have left yourself off the list of contributors >> though, even though you’ve been a central figure in its development :) So >> thanks to all accord & tcm contributors, including Benedict, for making >> this possible! >> >> On Tue, Mar 4, 2025, at 8:00 AM, Benedict Elliott Smith wrote: >> >> Hi everyone, >> >> It’s been exactly 3.5 years since the first commit to cassandra-accord. >> Yes, really, it’s been that long. >> >> We will be starting to validate the feature against real workloads in the >> near future, so we can’t sensibly push off merging much longer. The >> following is a brief run-down of the state of play. There are no known >> bugs, but there remain a number of caveats we will be incrementally >> addressing in the run-up to a full release: >> >> [1] Accord is likely to be SLOW until further optimisations are >> implemented >> [2] Schema changes have a number of hard edges >> [3] Validation is ongoing, so there are likely still a number of bugs to >> shake out >> [4] Many operator visibility/tooling/documentation improvements are >> pending >> >> To expand a little: >> >> [1] As of the last experiment we conducted, accord’s throughput was poor >> - also leading to higher LAN latencies. We have done no WAN experiments to >> date, but the protocol guarantees should already achieve better round-trip >> performance, in particular under contention. Improving throughput will be >> the main focus of attention once we are satisfied the protocol is otherwise >> stable, but our focus remains validation for the moment. >> [2] Schema changes have not yet been well integrated with TCM. Dropping a >> table for instance will currently cause problems if nodes are offline. >> [3] We have a range of validations we are already performing against >> cassandra-accord directly, and against its integration with Cassandra in >> cep-15-accord. We have run hundreds of billions of simulated transactions, >> and are still discovering some minor fault every few billion simulated >> transactions or so. There remains a lot more simulated validation to >> explore, as well as with real clusters serving real workloads. >> [4] There are already a range of virtual tables for exploring internal >> state in Accord, and reasonably good metric support. However, tracing is >> not yet supported, and our metric and virtual table integrations need some >> further development. >> [5] There are also other edge cases to address such as ensuring we do not >> reuse HLCs after restart, supporting ByteOrderPartitioner, and live >> migration from/to Paxos is undergoing fine-tuning and validation; probably >> there are some other things I am forgetting. >> >> Altogether the feature is fairly mature, despite these caveats. This is >> the fruit of the labour of a long list of contributors, including Aleksey >> Yeschenko, Alex Petrov, Ariel Weisberg, Blake Eggleston, Caleb Rackliffe >> and David Capwell, and represents a huge undertaking. It also wouldn’t have >> been possible without the work of Alex Petrov, Marcus Eriksson and Sam >> Tunnicliffe on delivering transactional cluster metadata. I hope you will >> join me in thanking them all for their contributions. >> >> Alex has also kindly produced some initial overview documentation for >> developers, that can be found here: >> https://github.com/apache/cassandra/blob/cep-15-accord/doc/modules/cassandra/pages/developing/accord/index.adoc. >> This will be expanded as time permits. >> >> Does anyone have any questions or concerns? >> >> >> > > -- > Dmitry Konstantinov >
