Given the extensiveness and complexity of the proposal I'd suggest leaving it a little longer (perhaps 4 weeks from the publish date?) for people to get a bit more familiarized and have the chance to comment before casting a vote. I glanced through the proposal - and it looks outstanding, very promising work guys! - but would like a bit more time to take a deeper look and digest it before potentially commenting on it.
Em ter., 14 de set. de 2021 às 17:30, bened...@apache.org < bened...@apache.org> escreveu: > Has anyone had a chance to read the drafts, and has any feedback or > questions? Does anybody still anticipate doing so in the near future? Or > shall we move to a vote? > > From: bened...@apache.org <bened...@apache.org> > Date: Tuesday, 7 September 2021 at 21:27 > To: dev@cassandra.apache.org <dev@cassandra.apache.org> > Subject: Re: [DISCUSS] CEP-15: General Purpose Transactions > Hi Jake, > > > What structural changes are planned to support an external dependency > project like this > > To add to Blake’s answer, in case there’s some confusion over this, the > proposal is to include this library within the Apache Cassandra project. So > I wouldn’t think of it as an external dependency. This PMC and community > will still have the usual oversight over direction and development, and > APIs will be developed solely with the intention of their integration with > Cassandra. > > > Will this effort eventually replace consistency levels in C*? > > I hope we’ll have some very related discussions around consistency levels > in the coming months more generally, but I don’t think that is tightly > coupled to this work. I agree with you both that we won’t want to > perpetuate the problems you’ve highlighted though. > > Henrik: > > I was referring to the property that Calvin transactions also need to be > sent to the cluster in a single shot > > Ah, yes. In that case I agree, and I tried to point to this direction in > an earlier email, where I discussed the use of scripting languages (i.e. > transactionally modifying the database with some subset of arbitrary > computation). I think the JVM is particularly suited to offering quite > powerful distributed transactions in this vein, and it will be interesting > to see what we might develop in this direction in future. > > > From: Jake Luciani <jak...@gmail.com> > Date: Tuesday, 7 September 2021 at 19:27 > To: dev@cassandra.apache.org <dev@cassandra.apache.org> > Subject: Re: [DISCUSS] CEP-15: General Purpose Transactions > Great thanks for the information > > On Tue, Sep 7, 2021 at 12:44 PM Blake Eggleston > <beggles...@apple.com.invalid> wrote: > > > Hi Jake, > > > > > 1. Will this effort eventually replace consistency levels in C*? I > ask > > > because one of the shortcomings of our paxos today is > > > it can be easily mixed with non serialized consistencies and therefore > > > users commonly break consistency by for example reading at CL.ONE while > > > also > > > using LWTs. > > > > This will likely require CLs to be specified at the schema level for > > tables using multi partition transactions. I’d expect this to be > available > > for other tables, but not required. > > > > > 2. What structural changes are planned to support an external > dependency > > > project like this? Are there some high level interfaces you expect the > > > project to adhere to? > > > > There will be some interfaces that need to be implemented in C* to > support > > the library. You can find the current interfaces in the accord.api > package, > > but these were written to support some initial testing, and not intended > > for integration into C* as is. Things are pretty fluid right now and will > > be rewritten / refactored multiple times over the next few months. > > > > Thanks, > > > > Blake > > > > > > > On Sun, Sep 5, 2021 at 10:33 AM bened...@apache.org < > bened...@apache.org > > > > > > wrote: > > > > > >> Wiki: > > >> > > > https://cwiki.apache.org/confluence/display/CASSANDRA/CEP-15%3A+General+Purpose+Transactions > > >> Whitepaper: > > >> > > > https://cwiki.apache.org/confluence/download/attachments/188744725/Accord.pdf > > >> < > > >> > > > https://cwiki.apache.org/confluence/download/attachments/188744725/Accord.pdf?version=1&modificationDate=1630847736966&api=v2 > > >>> > > >> Prototype: https://github.com/belliottsmith/accord > > >> > > >> Hi everyone, I’d like to propose this CEP for adoption by the > community. > > >> > > >> Cassandra has benefitted from LWTs for many years, but application > > >> developers that want to ensure consistency for complex operations must > > >> either accept the scalability bottleneck of serializing all related > > state > > >> through a single partition, or layer a complex state machine on top of > > the > > >> database. These are sophisticated and costly activities that our users > > >> should not be expected to undertake. Since distributed databases are > > >> beginning to offer distributed transactions with fewer caveats, it is > > past > > >> time for Cassandra to do so as well. > > >> > > >> This CEP proposes the use of several novel techniques that build upon > > >> research (that followed EPaxos) to deliver (non-interactive) general > > >> purpose distributed transactions. The approach is outlined in the > > wikipage > > >> and in more detail in the linked whitepaper. Importantly, by adopting > > this > > >> approach we will be the _only_ distributed database to offer global, > > >> scalable, strict serializable transactions in one wide area > round-trip. > > >> This would represent a significant improvement in the state of the > art, > > >> both in the academic literature and in commercial or open source > > offerings. > > >> > > >> This work has been partially realised in a prototype. This partial > > >> prototype has been verified against Jepsen.io’s Maelstrom library and > > >> dedicated in-tree strict serializability verification tools, but much > > work > > >> remains for the work to be production capable and integrated into > > Cassandra. > > >> > > >> I propose including the prototype in the project as a new source > > >> repository, to be developed as a standalone library for integration > into > > >> Cassandra. I hope the community sees the important value proposition > of > > >> this proposal, and will adopt the CEP after this discussion, so that > the > > >> library and its integration into Cassandra can be developed in > parallel > > and > > >> with the involvement of the wider community. > > >> > > > > > > > > > -- > > > http://twitter.com/tjake > > > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: dev-unsubscr...@cassandra.apache.org > > For additional commands, e-mail: dev-h...@cassandra.apache.org > > > > > > -- > http://twitter.com/tjake >
