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 >>>> >> >>>> >> > >>>> >> >>>> >> > >>>> >> >>>> >> >>>> >>>> >>>> >>> > > >
