Hooray! Huge thanks to all! Now, I have no more excuses — it's time to try it :-D
On Thu, 17 Apr 2025 at 23:42, Jordan West <jorda...@gmail.com> wrote: > Congrats all! My previous reservations (that have been addressed) aside, > this is an amazing milestone. Awesome, awesome work! > > Jordan > > On Thu, Apr 17, 2025 at 15:07 David Capwell <dcapw...@apple.com> wrote: > >> I have merged cep-15-accord into trunk. If you experience any issues >> please reach out to me >> >> >> On Apr 17, 2025, at 12:55 AM, Benedict Elliott Smith <bened...@apache.org> >> wrote: >> >> Final update: David has completed a second rebase after we reached parity >> with trunk on our CI, and has confirmed tests remain stable. So I expect >> CEP-15 to merge to trunk sometime today. >> >> No doubt there will be some unexpected disruption to others after a patch >> like this lands. Reach out via slack if you have any trouble. >> >> On 16 Mar 2025, at 10:44, Benedict Elliott Smith <bened...@apache.org> >> wrote: >> >> Hi everyone, >> >> To update you: the last patches we considered blockers have landed in the >> cep-15-accord branch. Caleb has now started rebasing the branch onto trunk. >> I expect there will be a few failing tests still to resolve at that point, >> but once they have been squashed we will proceed with the merge. >> >> There remains more work to do before release, and I will publish a >> detailed roadmap to Jira when I’m back in a couple of weeks. >> >> >> On 11 Mar 2025, at 20:12, Nate McCall <zznat...@gmail.com> wrote: >> >> It sounds like we are all pretty interested in seeing this feature land >> and the branch maintenance is causing overhead that could be spent on >> finalisation. +1 on merging, particularly given the feature flag work. >> >> Once more unto the breach 💪 >> >> On Fri, 7 Mar 2025 at 6:56 PM, Benedict <bened...@apache.org> wrote: >> >>> There are essentially three possible timelines to choose from here: >>> >>> 1) We agree in the next few days to merge to trunk. We will then >>> prioritise rebasing onto trunk and resolving any pre-merge items starting >>> next week. >>> 2) There’s some more debate and agreement to merge to trunk in a week or >>> two. In the meantime we will shift to internal-first development but we’ll >>> likely prioritise the above work as soon as we can, which may be in a few >>> weeks, so we can shift to trunk first development. >>> 3) We don’t agree to merge accord anytime soon, so we shift to >>> internal-first development for the time being. I’m not sure when we will >>> prioritise any of the above. >>> >>> Our resources are finite and we’ve exhausted them (literally), so it’s >>> pretty much pick one of the above. I don’t really mind which you pick, but >>> I won’t personally be prioritising merge after this third attempt. >>> >>> On 6 Mar 2025, at 22:01, Jon Haddad <j...@rustyrazorblade.com> wrote: >>> >>> >>> >>> Hmm... I took a look at the cep-15-accord branch in GitHub, it looks >>> like it's several hundred commits behind trunk. Since you'll need to >>> rebase again before merge *anyways*, would it make sense to do it once >>> more, and I can publish easy-cass-lab with the latest branch? If folks >>> have concerns, it's easy to fire up a cluster (I do it constantly) and try >>> it out. >>> >>> I think if we were to do this, out of consideration we should time box >>> the amount of time for an evaluation and unless someone raises an >>> objection, consider lazy consensus achieved. >>> >>> Jon >>> >>> >>> >>> On Thu, Mar 6, 2025 at 12:46 PM Benedict Elliott Smith < >>> bened...@apache.org> wrote: >>> >>>> Because we want to validate against the latest code in trunk, else we >>>> are validating stale behaviours. The cost of rebasing is high, so we do not >>>> do it frequently. That means we will likely stop developing OSS-first, as >>>> the focus will have to move to our internal branch that satisfies these >>>> criteria. >>>> >>>> Exactly what this might be for upstreaming I cannot say. Personally, I >>>> aim to work exclusively on the branch we are stabilising. If that is not >>>> trunk, the latency for my contributions being made public might be high, as >>>> I have a huge imbalance of over-investment to recoup, and anything >>>> unnecessary will be deferred. >>>> >>>> Since the feature is disabled, and the code is almost entirely >>>> isolated, I cannot imagine the cost to the community to removing this work >>>> would be very high. But, I do not intend to argue Accord’s case here. I >>>> will let you all decide. >>>> >>>> Please decide soon though, as it shapes our work planning. The positive >>>> reception so far had lead me to consider prioritising a move to trunk-first >>>> development within the next week or two, and the associated work that >>>> entails. However, if that was optimistic we will have to shift our plans. >>>> >>>> >>>> >>>> On 6 Mar 2025, at 20:16, Jordan West <jw...@apache.org> wrote: >>>> >>>> The work and effort in accord has been amazing. And I’m sure it sets a >>>> new standard for code quality and correctness testing which I’m also >>>> entirely behind. I also trust the folks working on it want to take it to >>>> the a fully production ready solution. But I’m worried about circumstances >>>> out of our control leaving us with a very complex feature that isn’t >>>> complete. >>>> >>>> I do have some questions. Could folks help me better understand why >>>> testing real workloads necessitates a merge (my understanding from the >>>> original reason is this is the impetus for why we would merge now)? Also I >>>> think the performance and scheme change caveats are rather large ones. One >>>> of accords promise was better performance and I think making schema changes >>>> with nodes down not being supported is a big gap. Could we have some >>>> criteria like “supports all the operations PaxosV2 supports” or “performs >>>> as well or better than PaxosV2 on [workload(s)]”? >>>> >>>> I understand waiting asks a lot of the authors in terms of baring the >>>> burden of a more complex merge. But I think we also need to consider what >>>> merging is asking the community to bear if the worst happens and we are >>>> unable to take the feature from its current state to something that can be >>>> widely used in production. >>>> >>>> >>>> Jordan >>>> >>>> >>>> On Wed, Mar 5, 2025 at 15:52 Blake Eggleston <bl...@ultrablake.com> >>>> wrote: >>>> >>>>> +1 to merging it >>>>> >>>>> On Wed, Mar 5, 2025, at 12:22 PM, Patrick McFadin wrote: >>>>> >>>>> You have my +1 >>>>> >>>>> On Wed, Mar 5, 2025 at 12:16 PM Benedict <bened...@apache.org> wrote: >>>>> > >>>>> > Correct, these caveats should only apply to tables that have >>>>> opted-in to accord. >>>>> > >>>>> > On 5 Mar 2025, at 20:08, Jeremiah Jordan <jerem...@apache.org> >>>>> wrote: >>>>> > >>>>> > >>>>> > So great to see all this hard work about to pay off! >>>>> > >>>>> > On the questions/concerns front, the only concern I would have >>>>> towards merging this to trunk is if any of the caveats apply when someone >>>>> is not using Accord. Assuming they only apply when the feature flag is >>>>> enabled, I see no reason not to get this merged into trunk once everyone >>>>> involved is happy with the state of it. >>>>> > >>>>> > -Jeremiah >>>>> > >>>>> > On Mar 5, 2025 at 12:15:23 PM, Benedict Elliott Smith < >>>>> bened...@apache.org> wrote: >>>>> >> >>>>> >> That depends on all of you lovely people :D >>>>> >> >>>>> >> I think we should have finished merging everything we want before >>>>> QA by ~Monday; certainly not much later. >>>>> >> >>>>> >> I think we have some upgrade and python dtest failures to address >>>>> as well. >>>>> >> >>>>> >> So it could be pretty soon if the community is supportive. >>>>> >> >>>>> >> On 5 Mar 2025, at 17:22, Patrick McFadin <pmcfa...@gmail.com> >>>>> wrote: >>>>> >> >>>>> >> >>>>> >> What is the timing for starting the merge process? I'm asking >>>>> because >>>>> >> >>>>> >> I have (yet another) presentation and this would be a cool update. >>>>> >> >>>>> >> >>>>> >> On Wed, Mar 5, 2025 at 1:22 AM Benedict Elliott Smith >>>>> >> >>>>> >> <bened...@apache.org> wrote: >>>>> >> >>>>> >> > >>>>> >> >>>>> >> > Thanks everyone. >>>>> >> >>>>> >> > >>>>> >> >>>>> >> > Jon - your help will be greatly appreciated. We’ll let you know >>>>> when we’ve got the cycles to invest in performance work (hopefully fairly >>>>> soon). I expect the first step will be improving visibility so we can >>>>> better understand what the system is doing (particularly the caching >>>>> layers), but we can dig in together when ready. >>>>> >> >>>>> >> > >>>>> >> >>>>> >> > On 4 Mar 2025, at 18:15, Jon Haddad <j...@rustyrazorblade.com> >>>>> wrote: >>>>> >> >>>>> >> > >>>>> >> >>>>> >> > 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 >>>>> >> >>>>> >> > >>>>> >> >>>>> >> > >>>>> >> >>>>> >> >>>>> >>>>> >>>>> >>>> >> >> >> -- Dmitry Konstantinov
