Ivan,
Seem the answer is "yes, we've got consensus". The issue [1] created. [1] https://issues.apache.org/jira/browse/IGNITE-12650 On Fri, 7 Feb 2020 at 21:33, Ivan Pavlukhin <vololo...@gmail.com> wrote: > > Folks, > > Do we have a consensus so far that MVCC should be annotated with > @IgniteExperimental? Are there any objections? > > Best regards, > Ivan Pavlukhin > > пт, 7 февр. 2020 г. в 15:58, Roman Kondakov <kondako...@mail.ru.invalid>: > > > > I absolutely agree with Alexey that MVCC architecture should be > > completely reviewed. Current implementation is uncompetitive with other > > solutions. It is slow by design. Here are some my points: > > - we use central coordinator for transactions ordering. This is very > > similar to what Calvin [1] systems do. But unlike them we also use 2pc > > for distributed commit. So, we always have several additional network > > hops for each transaction and every Calvin system (FaunaDB, YandexDB) > > will outperform Ignite by design. > > - We write uncommitted data to the page memory and WAL and this slows > > down transactions even more. > > > > I am a supporter of complete revising of the MVCC design. > > > > [1] http://cs.yale.edu/homes/thomson/publications/calvin-sigmod12.pdf > > > > -- > > Kind Regards > > Roman Kondakov > > > > > > On 07.02.2020 15:21, Alexei Scherbakov wrote: > > > My point is MVCC should be redone from scratch without messing with other > > > pars of code. > > > > > > Currently it's spaghetti unmaintanable code. > > > > > > пт, 7 февр. 2020 г. в 14:52, Ivan Pavlukhin <vololo...@gmail.com>: > > > > > >> My humble opinion. > > >> > > >> We need MVCC because it is our way to SQL transactions. SQL is a very > > >> important user API (as you might know there is an active work on new > > >> SQL engine). Fair SQL transactions is a supplementary and quite needed > > >> feature, users ask about it on user list. I believe it is a future of > > >> Ignite. > > >> > > >> Best regards, > > >> Ivan Pavlukhin > > >> > > >> пт, 7 февр. 2020 г. в 13:23, Seliverstov Igor <gvvinbl...@gmail.com>: > > >>> > > >>> Note that someone uses it > > >>> > > >>> Main problem is a recovery process when persistence enabled and a > > >> cluster have more than one node. > > >>> > > >>> It is a problem even for regular transactional caches, the main > > >> difference - MVCC detects any inconsistencies while regular transactional > > >> caches may ignore it without any notification > > >>> > > >>> In other cases it works fine and provides promised guaranties. > > >>> > > >>> Of course there are several minor issues like performance ones, but > > >> there is a plan how to solve them (I could share it if anybody is > > >> curious) > > >>> > > >>> My opinion we should solve consistency issues first and finalize MVCC > > >> after that. > > >>> > > >>> Until that it’s OK to have it as experimental feature. > > >>> > > >>> Regards, > > >>> Igor > > >>> > > >>>> 6 февр. 2020 г., в 21:25, Alexei Scherbakov < > > >> alexey.scherbak...@gmail.com> написал(а): > > >>>> > > >>>> I'm strongly support removal of MVCC from master. > > >>>> > > >>>> At the current state it bloats code base and should be reworked from > > >>>> scratch using separate code base. > > >>>> > > >>>> чт, 6 февр. 2020 г. в 19:45, Ilya Kasnacheev < > > >> ilya.kasnach...@gmail.com>: > > >>>> > > >>>>> Hello! > > >>>>> > > >>>>> Please keep in mind that you need to create a separate proposal voting > > >>>>> thread if you really like it to count. I wonder if Dmitry Pavlov can > > >> help > > >>>>> us with the procedure. > > >>>>> > > >>>>> Otherwise, I think it makes total sense to restrict MVCC clusters to > > >> only > > >>>>> have MVCC caches or REPLICATED TRANSACTIONAL caches (are they > > >> compatible in > > >>>>> our current implementation) and no ATOMIC caches at all. > > >>>>> > > >>>>> Regards, > > >>>>> -- > > >>>>> Ilya Kasnacheev > > >>>>> > > >>>>> > > >>>>> чт, 6 февр. 2020 г. в 19:41, Maxim Muzafarov <mmu...@apache.org>: > > >>>>> > > >>>>>> Ilya, > > >>>>>> > > >>>>>> > > >>>>>> 1. MVCC support requires code maintenance for other developed > > >> features > > >>>>>> even if has not used and disabled. Currently, we've got an x2 level > > >> of > > >>>>>> difficulty for implementation of new features. > > >>>>>> > > >>>>>> 2. It would be much easy to develop and support clusters with > > >>>>>> mvcc-caches only rather than have a mixed configuration. With this > > >>>>>> option we can dramatically reduce the amount of codebase removing > > >> from > > >>>>>> mvcc-branch local, atomic, tx caches. > > >>>>>> > > >>>>>> > > >>>>>> So, I'm +1 to remove it from the master branch and mark the current > > >>>>>> API with @IgniteExperimental. > > >>>>>> > > >>>>>> On Thu, 6 Feb 2020 at 19:29, Ilya Kasnacheev < > > >> ilya.kasnach...@gmail.com> > > >>>>>> wrote: > > >>>>>>> > > >>>>>>> Hello! > > >>>>>>> > > >>>>>>> Why would we drop MVCC!? > > >>>>>>> > > >>>>>>> I can totally imagine a scenario where a large Ignite user surfaces > > >>>>> with > > >>>>>>> fixes for MVCC mode, if it is kept as an experimental feature. Then > > >>>>> maybe > > >>>>>>> it will graduate to beta some time in future. > > >>>>>>> > > >>>>>>> If it does too much strain on the TC, let's discuss that, but I > > >> don't > > >>>>>>> remember problems with TC load lately, so maybe this is a moot > > >> point. > > >>>>>>> > > >>>>>>> Regards, > > >>>>>>> -- > > >>>>>>> Ilya Kasnacheev > > >>>>>>> > > >>>>>>> > > >>>>>>> чт, 6 февр. 2020 г. в 15:27, Nikolay Izhikov <nizhi...@apache.org>: > > >>>>>>> > > >>>>>>>>> By the way, is there any reason to have this code in the master > > >>>>>> branch > > >>>>>>>> > > >>>>>>>> I support removal MVCC from master. > > >>>>>>>> > > >>>>>>>> > > >>>>>>>>> 6 февр. 2020 г., в 15:26, Andrey Gura <ag...@apache.org> > > >>>>> написал(а): > > >>>>>>>>> > > >>>>>>>>> +1 > > >>>>>>>>> > > >>>>>>>>> By the way, is there any reason to have this code in the master > > >>>>>>>>> branch? It seems feature is in unsupportable state and just wastes > > >>>>> TC > > >>>>>>>>> time and our effort to support MVCC related tests. > > >>>>>>>>> > > >>>>>>>>> On Thu, Feb 6, 2020 at 2:44 PM Alexey Goncharuk > > >>>>>>>>> <alexey.goncha...@gmail.com> wrote: > > >>>>>>>>>> > > >>>>>>>>>> Agree, let's mark MVCC experimental. > > >>>>>>>>>> > > >>>>>>>>>> Stephen, the annotation serves as an additional > > >>>>> documentation-style > > >>>>>>>> marker. > > >>>>>>>>>> For now there are no compile-time warnings when the API is used. > > >>>>>>>>>> > > >>>>>>>>>> чт, 6 февр. 2020 г. в 14:35, Stephen Darlington < > > >>>>>>>>>> stephen.darling...@gridgain.com>: > > >>>>>>>>>> > > >>>>>>>>>>> Yes! I’ve already seen people try to use this without awareness > > >>>>>> that > > >>>>>>>> it’s > > >>>>>>>>>>> not production ready. > > >>>>>>>>>>> > > >>>>>>>>>>> What happens with the annotation, incidentally? Is it just in > > >> the > > >>>>>>>>>>> documentation or do you get a compile-time warning? > > >>>>>>>>>>> > > >>>>>>>>>>>> On 6 Feb 2020, at 11:32, Nikolay Izhikov <nizhi...@apache.org> > > >>>>>> wrote: > > >>>>>>>>>>>> > > >>>>>>>>>>>> Hello, Igniters. > > >>>>>>>>>>>> > > >>>>>>>>>>>> Should we mark MVCC feature with the new @IgniteExperimental? > > >>>>>>>>>>>> > > >>>>>>>>>>>> We explicitly note users that MVCC has beta status, for now [1] > > >>>>>>>>>>>> > > >>>>>>>>>>>>> Beta version of Transactional SQL and MVCC > > >>>>>>>>>>>>> In Ignite v2.7, Transactional SQL and MVCC are released as > > >> beta > > >>>>>>>>>>> versions to allow users to experiment and share feedback. > > >>>>>>>>>>>>> This version of Transactional SQL and MVCC should not be > > >>>>>> considered > > >>>>>>>> for > > >>>>>>>>>>> production. > > >>>>>>>>>>>> > > >>>>>>>>>>>> > > >>>>>>>>>>>> [1] > > >>>>>>>> > > >> https://apacheignite.readme.io/docs/multiversion-concurrency-control > > >>>>>>>>>>>> > > >>>>>>>>>>>> > > >>>>>>>>>>> > > >>>>>>>>>>> > > >>>>>>>>>>> > > >>>>>>>> > > >>>>>>>> > > >>>>>> > > >>>>> > > >>>> > > >>>> > > >>>> -- > > >>>> > > >>>> Best regards, > > >>>> Alexei Scherbakov > > >>> > > >> > > > > > >
