Re: Re[2]: Deprecating LOCAL cache

[Maxim Muzafarov <mm...@apache.org>]

Folks,


Let's back to discussion.
We've already deprecated local caches [1], so it's time to remove them.


I've prepared the PR, please check:

- https://issues.apache.org/jira/browse/IGNITE-15759
- https://github.com/apache/ignite/pull/10157


[1] https://issues.apache.org/jira/browse/IGNITE-15756

On Wed, 15 Sept 2021 at 09:33, Zhenya Stanilovsky
<ar...@mail.ru.invalid> wrote:
>
>
>
> Ok, we can use node filters in such a case, i understand )
>
>
>
> >I just dream up ) If some one have cached web session layer over
> >ignite with sticky cookie [1] and cross cache transaction logic through
> >local and global caches how this schema will transform without local ?
> >
> >[1]
> >https://www.imperva.com/learn/availability/sticky-session-persistence-and-cookies/
> >
> >
> >> I am not about creation per se, but creation from a thin client side.
> >>
> >> This feature simply doesn't work as expected, broken and impossible to
> >> fix.
> >> It cannot broke any code, because it was already broken and it is
> >> impossible to use in production.
> >> But it still can embarrass newcomers and brings a lot of frustration.
> >>
> >> It is much more safe to ban a creation of LOCAL caches from thin clients.
> >>
> >> But it can survive for a while for ignite cluster nodes, client and
> >> server.
> >>
> >> вт, 14 сент. 2021 г. в 14:06, Maxim Muzafarov <  mmuzaf@apache.org >:
> >>
> >>> Ivan,
> >>>
> >>> I don't think we should rush with this. Banning the creation of LOCAL
> >>> caches without a warning through the code sounds not good. Will it be
> >>> better to do everything in three steps (releases)? 2.12 deprecate,
> >>> 2.13 forbid new cache creation, 2.14 remove.
> >>>
> >>> On Tue, 14 Sept 2021 at 12:09, Ivan Daschinsky <  ivandasch@gmail.com >
> >>> wrote:
> >>> >
> >>> > Few thoughts about LOCAL caches on thin client:
> >>> >
> >>> > 1. If partition awareness is disabled:
> >>> > a. Inconsistent behaviour if node to which client is connected goes
> >>> down.
> >>> > 2. If partition awareness is enabled:
> >>> > a. For Java and .NET -- same as 1a
> >>> > b. For C++ and python -- use random routing for caches that are not
> >>> > PARTITIONED, so inconsistent behaviour from the beginning.
> >>> >
> >>> > So I suppose we should ban creation of LOCAL caches from thin client
> >>> in
> >>> > 2.12 (fail attempt to create such caches in ClientRequestHandler
> >>> >
> >>> > вт, 14 сент. 2021 г. в 11:31, Ivan Daschinsky <  ivandasch@gmail.com >:
> >>> >
> >>> > > >> Unsupported operation exception.
> >>> > > Binary protocol doesn't have a concept of exception, only error
> >>> status
> >>> and
> >>> > > message, but it is just a remark
> >>> > > I suppose that response with error status and message is ok, but
> >>> may be
> >>> > > others have different opinion?
> >>> > >
> >>> > > >> Removal should happen at 2.13.
> >>> > > A few thin clients are released separately. I suppose that it is
> >>> better to
> >>> > > remove this feature from pyignite a little bit earlier.
> >>> > >
> >>> > > вт, 14 сент. 2021 г. в 11:21, Anton Vinogradov <  av@apache.org >:
> >>> > >
> >>> > >> > 1. What is expected behaviour if an old thin client requests
> >>> creation of
> >>> > >> > LOCAL cache on the newest ignite cluster?
> >>> > >> Unsupported operation exception.
> >>> > >>
> >>> > >> > 2. Should we completely remove LOCAL caches support in thin
> >>> clients
> >>> > >> (i.e.
> >>> > >> pyignite) before 2.13 release?
> >>> > >> Removal should happen at 2.13.
> >>> > >>
> >>> > >> On Tue, Sep 14, 2021 at 10:30 AM Ivan Daschinsky <
> >>>  ivandasch@gmail.com
> >>> >
> >>> > >> wrote:
> >>> > >>
> >>> > >> > >> 2. 2.13 - complete removal LOCAL caches from codebase.
> >>> > >> > Let's discuss this step with more details.
> >>> > >> > 1. What is expected behaviour if an old thin client requests
> >>> creation of
> >>> > >> > LOCAL cache on the newest ignite cluster?
> >>> > >> > 2. Should we completely remove LOCAL caches support in thin
> >>> clients
> >>> > >> (i.e.
> >>> > >> > pyignite) before 2.13 release?
> >>> > >> >
> >>> > >> > вт, 14 сент. 2021 г. в 10:11, Nikolay Izhikov <
> >>>  nizhikov@apache.org
> >>> >:
> >>> > >> >
> >>> > >> > > I proposed the following plan:
> >>> > >> > >
> >>> > >> > > 1. 2.12 - deprecation of LOCAL caches.
> >>> > >> > > 2. 2.13 - complete removal LOCAL caches from codebase.
> >>> > >> > >
> >>> > >> > > > 13 сент. 2021 г., в 13:30, Ivan Daschinsky <
> >>>  ivandasch@gmail.com
> >>> >
> >>> > >> > > написал(а):
> >>> > >> > > >
> >>> > >> > > > I personally support deprecation, but we should at least
> >>> have a
> >>> > >> plan.
> >>> > >> > > > I suppose that putting annotations and removing documentation
> >>> are
> >>> > >> not
> >>> > >> > > > enough.
> >>> > >> > > >
> >>> > >> > > >
> >>> > >> > > > пн, 13 сент. 2021 г. в 13:22, Maxim Muzafarov <
> >>>  mmuzaf@apache.org >:
> >>> > >> > > >
> >>> > >> > > >> Ivan,
> >>> > >> > > >>
> >>> > >> > > >> I don't think we can remove LOCAL caches at the nearest
> >>> time,
> >>> so
> >>> > >> there
> >>> > >> > > >> is no plan for that. I can only imagine a single release
> >>> that
> >>> will
> >>> > >> > > >> contain all the breaking changes we want to apply in 2.x
> >>> version.
> >>> > >> > > >>
> >>> > >> > > >> My point here is only about deprecation:
> >>> > >> > > >> - there are a lot of motivation points to remove written in
> >>> this
> >>> > >> > thread;
> >>> > >> > > >> - I always hear from the support team that they do not
> >>> recommend
> >>> > >> using
> >>> > >> > > >> local caches;
> >>> > >> > > >> - I haven't seen any bugs fixed for a long time for local
> >>> caches
> >>> > >> > > >> (suppose that we are not maintaining them);
> >>> > >> > > >>
> >>> > >> > > >> I just want to make sure that all these points are reflected
> >>> in the
> >>> > >> > > >> code base, so propose to mark them as deprecated.
> >>> > >> > > >>
> >>> > >> > > >> On Mon, 13 Sept 2021 at 11:29, Ivan Daschinsky <
> >>> > >>  ivandasch@gmail.com >
> >>> > >> > > >> wrote:
> >>> > >> > > >>>
> >>> > >> > > >>> Hi, Maxim. And what is the plan of removing this
> >>> functionality?
> >>> > >> And I
> >>> > >> > > >> also
> >>> > >> > > >>> have some questions regarding deprecation in binary
> >>> protocol
> >>> > >> > > >>>
> >>> > >> > > >>> Currently thin client binary protocol
> >>> > >> > > >>> 1. Does support LOCAL caches
> >>> > >> > > >>> 2. Does not support node filters.
> >>> > >> > > >>>
> >>> > >> > > >>> I can hardly imagine the usefulness of this feature on thin
> >>> > >> clients,
> >>> > >> > > >>> especially with partition awareness, but nevertheless.
> >>> > >> > > >>> What is expected behaviour if this feature is removed from
> >>> newest
> >>> > >> > > version
> >>> > >> > > >>> of Apache Ignite server and and and old client is
> >>> requesting
> >>> > >> > > >>> creation of LOCAL cache?
> >>> > >> > > >>>
> >>> > >> > > >>> вс, 12 сент. 2021 г. в 15:10, Maxim Muzafarov <
> >>>  mmuzaf@apache.org
> >>> > >> >:
> >>> > >> > > >>>
> >>> > >> > > >>>> Folks,
> >>> > >> > > >>>>
> >>> > >> > > >>>> Let's get back to the discussion of obsolete LOCAL caches
> >>> since a
> >>> > >> > lot
> >>> > >> > > >>>> of time has passed since the last discussion.
> >>> > >> > > >>>> I've created an issue [1] for deprecation. Let's deprecate
> >>> them
> >>> > >> at
> >>> > >> > > >>>> least at the next 2.12 release.
> >>> > >> > > >>>>
> >>> > >> > > >>>> WDYT?
> >>> > >> > > >>>>
> >>> > >> > > >>>>
> >>> > >> > > >>>> [1]  https://issues.apache.org/jira/browse/IGNITE-15499
> >>> > >> > > >>>>
> >>> > >> > > >>>> On Fri, 27 Jul 2018 at 20:59, Valentin Kulichenko
> >>> > >> > > >>>> <  valentin.kulichenko@gmail.com > wrote:
> >>> > >> > > >>>>>
> >>> > >> > > >>>>> Guys,
> >>> > >> > > >>>>>
> >>> > >> > > >>>>> Use cases for local caches are rare, but they definitely
> >>> exist.
> >>> > >> I
> >>> > >> > > >> don't
> >>> > >> > > >>>>> think it's a very good idea to deprecate this
> >>> functionality
> >>> at
> >>> > >> this
> >>> > >> > > >>>> point.
> >>> > >> > > >>>>>
> >>> > >> > > >>>>> At the same point, it's obviously not the most critical
> >>> part of
> >>> > >> the
> >>> > >> > > >>>>> product, so maintaining the whole separate implementation
> >>> for
> >>> > >> it is
> >>> > >> > > >>>>> probably an overkill. We had exact same story with
> >>> replicated
> >>> > >> > caches
> >>> > >> > > >> btw
> >>> > >> > > >>>> -
> >>> > >> > > >>>>> they were implemented separately which caused
> >>> maintainability
> >>> > >> > > >> issues, and
> >>> > >> > > >>>>> we ended up removing this separate implementation. If we
> >>> have
> >>> > >> the
> >>> > >> > > >> same
> >>> > >> > > >>>>> situation here, let's use the same solution.
> >>> > >> > > >>>>>
> >>> > >> > > >>>>> -Val
> >>> > >> > > >>>>>
> >>> > >> > > >>>>> On Fri, Jul 27, 2018 at 3:05 AM Dmitry Pavlov <
> >>> > >> >  dpavlov.spb@gmail.com
> >>> > >> > > >>>
> >>> > >> > > >>>> wrote:
> >>> > >> > > >>>>>
> >>> > >> > > >>>>>> Hi Dmitriy,
> >>> > >> > > >>>>>>
> >>> > >> > > >>>>>> I would like to stress this: I'm not saying local cache
> >>> it
> >>> > >> > > >> useless. I'm
> >>> > >> > > >>>>>> supposing it is not used widely. I want to figure out if
> >>> I'm
> >>> > >> > > >> mistaking.
> >>> > >> > > >>>>>>
> >>> > >> > > >>>>>> All folks involved into user list says it is not used,
> >>> so
> >>> why
> >>> > >> not
> >>> > >> > > >> to
> >>> > >> > > >>>>>> deprecate? If we make a mistake, somebody will come to
> >>> user
> >>> > >> list
> >>> > >> > > >> and
> >>> > >> > > >>>> say,
> >>> > >> > > >>>>>> 'Hey, why did you deprecate this, it is used for... in
> >>> my
> >>> > >> project'
> >>> > >> > > >>>>>>
> >>> > >> > > >>>>>> Being very experienced Igniter you probably know real
> >>> life
> >>> > >> usage
> >>> > >> > > >>>> examples.
> >>> > >> > > >>>>>> And I appreciate if you or somebody else in community
> >>> could
> >>> > >> share
> >>> > >> > > >> it.
> >>> > >> > > >>>>>>
> >>> > >> > > >>>>>> Sincerely,
> >>> > >> > > >>>>>> Dmitriy Pavlov
> >>> > >> > > >>>>>>
> >>> > >> > > >>>>>> пт, 27 июл. 2018 г. в 1:04, Dmitriy Setrakyan <
> >>> > >> > > >>  dsetrakyan@apache.org >:
> >>> > >> > > >>>>>>
> >>> > >> > > >>>>>>> Guys,
> >>> > >> > > >>>>>>>
> >>> > >> > > >>>>>>> I just want to make sure we are all on the same page.
> >>> The
> >>> main
> >>> > >> > > >> use
> >>> > >> > > >>>> case
> >>> > >> > > >>>>>> for
> >>> > >> > > >>>>>>> LOCAL caches is to have a local hash map querable with
> >>> SQL and
> >>> > >> > > >>>>>>> automatically persisted to a 3rd party DB.
> >>> > >> > > >>>>>>>
> >>> > >> > > >>>>>>> I want to discourage people from saying "nobody needs
> >>> some
> >>> > >> > > >> feature".
> >>> > >> > > >>>> None
> >>> > >> > > >>>>>>> of the people in this discussion are users of any
> >>> features -
> >>> > >> we
> >>> > >> > > >> are
> >>> > >> > > >>>> all
> >>> > >> > > >>>>>>> developers of the features. Instead of guessing
> >>> whether to
> >>> > >> > > >> deprecate
> >>> > >> > > >>>>>>> something or not, I would actually see if it is even
> >>> worth a
> >>> > >> > > >>>> discussion.
> >>> > >> > > >>>>>>> How much effort is required to fix the bug found in the
> >>> LOCAL
> >>> > >> > > >> cache?
> >>> > >> > > >>>>>>>
> >>> > >> > > >>>>>>> D.
> >>> > >> > > >>>>>>>
> >>> > >> > > >>>>>>> On Thu, Jul 26, 2018 at 12:19 PM, Dmitry Pavlov <
> >>> > >> > > >>>>  dpavlov.spb@gmail.com >
> >>> > >> > > >>>>>>> wrote:
> >>> > >> > > >>>>>>>
> >>> > >> > > >>>>>>>> Hi Alexey,
> >>> > >> > > >>>>>>>>
> >>> > >> > > >>>>>>>> There is nothing to be sorry about :) Сommunity
> >>> appreciates
> >>> > >> an
> >>> > >> > > >>>>>>> alternative
> >>> > >> > > >>>>>>>> vision, this allows us to make as informed decisions
> >>> as
> >>> it
> >>> > >> > > >>>> possible.
> >>> > >> > > >>>>>>>>
> >>> > >> > > >>>>>>>> Thank you for finding this fact, it is very
> >>> interesting.
> >>> > >> > > >>>>>>>>
> >>> > >> > > >>>>>>>> I'm not sure all these examples were prepared by
> >>> experienced
> >>> > >> > > >> Ignite
> >>> > >> > > >>>>>>> users.
> >>> > >> > > >>>>>>>> So idea of deprecation may have one more argument.
> >>> > >> Deprecation
> >>> > >> > > >> will
> >>> > >> > > >>>>>> help
> >>> > >> > > >>>>>>> us
> >>> > >> > > >>>>>>>> to inform users about LOCAL cache: Probably local
> >>> cache
> >>> is
> >>> > >> not
> >>> > >> > > >> what
> >>> > >> > > >>>>>> they
> >>> > >> > > >>>>>>>> need.
> >>> > >> > > >>>>>>>>
> >>> > >> > > >>>>>>>> Sincerely,
> >>> > >> > > >>>>>>>> Dmitriy Pavlov
> >>> > >> > > >>>>>>>>
> >>> > >> > > >>>>>>>> чт, 26 июл. 2018 г. в 16:57, Alexey Zinoviev <
> >>> > >> > > >>>>  zaleslaw.sin@gmail.com >:
> >>> > >> > > >>>>>>>>
> >>> > >> > > >>>>>>>>> Sorry, guys, I'll put my 1 cent
> >>> > >> > > >>>>>>>>>
> >>> > >> > > >>>>>>>>> I'd like this idea "Implement LOCAL caches as
> >>> PARTITIONED
> >>> > >> > > >> caches
> >>> > >> > > >>>>>> over
> >>> > >> > > >>>>>>>> the
> >>> > >> > > >>>>>>>>> local node."
> >>> > >> > > >>>>>>>>> It make sense for examples/testing in
> >>> pseudo-distributed
> >>> > >> mode
> >>> > >> > > >>>> and so
> >>> > >> > > >>>>>>> far.
> >>> > >> > > >>>>>>>>>
> >>> > >> > > >>>>>>>>> But I think that the deprecation based on user-list
> >>> mentions
> >>> > >> > > >> is a
> >>> > >> > > >>>>>> wrong
> >>> > >> > > >>>>>>>>> way. Please look here
> >>> > >> > > >>>>>>>>>
> >>> > >> > > >>>>>>
> >>> > >> > > >>
> >>> > >> >
> >>>  https://github.com/search?q=%22CacheMode.LOCAL%22+%26+ignite&type=Code
> >>> > >> > > >>>>>>>>> There a lot of hello world examples with LOCAL mode.
> >>> > >> > > >>>>>>>>>
> >>> > >> > > >>>>>>>>> And of course, we can ask about that on user-list,
> >>> not
> >>> here,
> >>> > >> > > >> to
> >>> > >> > > >>>> vote
> >>> > >> > > >>>>>>> for
> >>> > >> > > >>>>>>>>> the deprecation like this.
> >>> > >> > > >>>>>>>>>
> >>> > >> > > >>>>>>>>> 2018-07-26 11:23 GMT+03:00 Vladimir Ozerov <
> >>> > >> > > >>  vozerov@gridgain.com
> >>> > >> > > >>>>> :
> >>> > >> > > >>>>>>>>>
> >>> > >> > > >>>>>>>>>> I meant LOCAL + non-LOCAL transactions of course.
> >>> > >> > > >>>>>>>>>>
> >>> > >> > > >>>>>>>>>> On Wed, Jul 25, 2018 at 10:42 PM Dmitriy Setrakyan <
> >>> > >> > > >>>>>>>>>  dsetrakyan@apache.org >
> >>> > >> > > >>>>>>>>>> wrote:
> >>> > >> > > >>>>>>>>>>
> >>> > >> > > >>>>>>>>>>> Vladimir,
> >>> > >> > > >>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>> Are you suggesting that a user cannot span more
> >>> than
> >>> one
> >>> > >> > > >>>> local
> >>> > >> > > >>>>>>> cache
> >>> > >> > > >>>>>>>>> in a
> >>> > >> > > >>>>>>>>>>> cross cache LOCAL transactions. This is extremely
> >>> > >> > > >> surprising
> >>> > >> > > >>>> to
> >>> > >> > > >>>>>> me,
> >>> > >> > > >>>>>>>> as
> >>> > >> > > >>>>>>>>> it
> >>> > >> > > >>>>>>>>>>> would require almost no effort to support it. As
> >>> far
> >>> as
> >>> > >> > > >>>> mixing
> >>> > >> > > >>>>>> the
> >>> > >> > > >>>>>>>>> local
> >>> > >> > > >>>>>>>>>>> caches with distributed caches, then I agree,
> >>> cross-cache
> >>> > >> > > >>>>>>>> transactions
> >>> > >> > > >>>>>>>>> do
> >>> > >> > > >>>>>>>>>>> not make sense.
> >>> > >> > > >>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>> I am not sure why deprecating local caches has
> >>> become
> >>> a
> >>> > >> > > >>>> pressing
> >>> > >> > > >>>>>>>>> issue. I
> >>> > >> > > >>>>>>>>>>> can see that there are a few bugs, but why not just
> >>> fix
> >>> > >> > > >> them
> >>> > >> > > >>>> and
> >>> > >> > > >>>>>>> move
> >>> > >> > > >>>>>>>>> on?
> >>> > >> > > >>>>>>>>>>> Can someone explain why supporting LOCAL caches is
> >>> such a
> >>> > >> > > >>>> burden?
> >>> > >> > > >>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>> Having said that, I am not completely opposed to
> >>> > >> > > >> deprecating
> >>> > >> > > >>>>>> LOCAL
> >>> > >> > > >>>>>>>>>> caches.
> >>> > >> > > >>>>>>>>>>> I just want to know why.
> >>> > >> > > >>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>> D.
> >>> > >> > > >>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>> On Wed, Jul 25, 2018 at 10:55 AM, Vladimir Ozerov <
> >>> > >> > > >>>>>>>>>  vozerov@gridgain.com >
> >>> > >> > > >>>>>>>>>>> wrote:
> >>> > >> > > >>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>> Dima,
> >>> > >> > > >>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>> LOCAL cache adds very little value to the
> >>> product. It
> >>> > >> > > >>>> doesn't
> >>> > >> > > >>>>>>>> support
> >>> > >> > > >>>>>>>>>>>> cross-cache transactions, consumes a lot of
> >>> memory,
> >>> > >> > > >> much
> >>> > >> > > >>>> slower
> >>> > >> > > >>>>>>>> than
> >>> > >> > > >>>>>>>>>> any
> >>> > >> > > >>>>>>>>>>>> widely-used concurrent hash map. Let's go the same
> >>> way
> >>> > >> > > >> as
> >>> > >> > > >>>> Java
> >>> > >> > > >>>>>> -
> >>> > >> > > >>>>>>>> mark
> >>> > >> > > >>>>>>>>>>> LOCAL
> >>> > >> > > >>>>>>>>>>>> cache as "deprecated for removal", and then
> >>> remove it
> >>> > >> > > >> in
> >>> > >> > > >>>> 3.0.
> >>> > >> > > >>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>> On Wed, Jul 25, 2018 at 12:10 PM Dmitrii Ryabov <
> >>> > >> > > >>>>>>>>>  somefireone@gmail.com
> >>> > >> > > >>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>> wrote:
> >>> > >> > > >>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>> +1 to make LOCAL as filtered PARTITIONED cache. I
> >>> > >> > > >> think
> >>> > >> > > >>>> it
> >>> > >> > > >>>>>>> would
> >>> > >> > > >>>>>>>> be
> >>> > >> > > >>>>>>>>>>> much
> >>> > >> > > >>>>>>>>>>>>> easier and faster than fixing all bugs.
> >>> > >> > > >>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>> 2018-07-25 11:51 GMT+03:00 Dmitriy Setrakyan <
> >>> > >> > > >>>>>>>>>  dsetrakyan@apache.org
> >>> > >> > > >>>>>>>>>>> :
> >>> > >> > > >>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>>> I would stay away from deprecating such huge
> >>> > >> > > >> pieces as
> >>> > >> > > >>>> a
> >>> > >> > > >>>>>>> whole
> >>> > >> > > >>>>>>>>>> LOCAL
> >>> > >> > > >>>>>>>>>>>>> cache.
> >>> > >> > > >>>>>>>>>>>>>> In retrospect, we should probably not even have
> >>> > >> > > >> LOCAL
> >>> > >> > > >>>>>> caches,
> >>> > >> > > >>>>>>>> but
> >>> > >> > > >>>>>>>>>>> now I
> >>> > >> > > >>>>>>>>>>>>> am
> >>> > >> > > >>>>>>>>>>>>>> certain that it is used by many users.
> >>> > >> > > >>>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>>> I would do one of the following, whichever one
> >>> is
> >>> > >> > > >>>> easier:
> >>> > >> > > >>>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>>> - Fix the issues found with LOCAL caches,
> >>> > >> > > >> including
> >>> > >> > > >>>>>>>>> persistence
> >>> > >> > > >>>>>>>>>>>>> support
> >>> > >> > > >>>>>>>>>>>>>> - Implement LOCAL caches as PARTITIONED caches
> >>> > >> > > >> over
> >>> > >> > > >>>> the
> >>> > >> > > >>>>>>>> local
> >>> > >> > > >>>>>>>>>>> node.
> >>> > >> > > >>>>>>>>>>>> In
> >>> > >> > > >>>>>>>>>>>>>> this case, we would have to hide any
> >>> > >> > > >>>>>> distribution-related
> >>> > >> > > >>>>>>>>> config
> >>> > >> > > >>>>>>>>>>>> from
> >>> > >> > > >>>>>>>>>>>>>> users, like affinity function, for example.
> >>> > >> > > >>>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>>> D.
> >>> > >> > > >>>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>>> On Wed, Jul 25, 2018 at 9:05 AM, Valentin
> >>> > >> > > >> Kulichenko <
> >>> > >> > > >>>>>>>>>>>>>>  valentin.kulichenko@gmail.com > wrote:
> >>> > >> > > >>>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>>>> It sounds like the main drawback of LOCAL cache
> >>> > >> > > >> is
> >>> > >> > > >>>> that
> >>> > >> > > >>>>>>> it's
> >>> > >> > > >>>>>>>>>>>>> implemented
> >>> > >> > > >>>>>>>>>>>>>>> separately and therefore has to be maintained
> >>> > >> > > >>>> separately.
> >>> > >> > > >>>>>>> If
> >>> > >> > > >>>>>>>>>> that's
> >>> > >> > > >>>>>>>>>>>> the
> >>> > >> > > >>>>>>>>>>>>>>> only issue, why not keep LOCAL cache mode on
> >>> > >> > > >> public
> >>> > >> > > >>>> API,
> >>> > >> > > >>>>>>> but
> >>> > >> > > >>>>>>>>>>>> implement
> >>> > >> > > >>>>>>>>>>>>> it
> >>> > >> > > >>>>>>>>>>>>>>> as a PARTITIONED cache with a node filter
> >>> > >> > > >> forcefully
> >>> > >> > > >>>> set?
> >>> > >> > > >>>>>>>>> That's
> >>> > >> > > >>>>>>>>>>>>> similar
> >>> > >> > > >>>>>>>>>>>>>> to
> >>> > >> > > >>>>>>>>>>>>>>> what we do with REPLICATED caches which are
> >>> > >> > > >> actually
> >>> > >> > > >>>>>>>>> PARTITIONED
> >>> > >> > > >>>>>>>>>>> with
> >>> > >> > > >>>>>>>>>>>>>>> infinite number of backups.
> >>> > >> > > >>>>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>>>> This way we fix the issues described by Stan
> >>> and
> >>> > >> > > >>>> don't
> >>> > >> > > >>>>>> have
> >>> > >> > > >>>>>>>> to
> >>> > >> > > >>>>>>>>>>>>> deprecate
> >>> > >> > > >>>>>>>>>>>>>>> anything.
> >>> > >> > > >>>>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>>>> -Val
> >>> > >> > > >>>>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>>>> On Wed, Jul 25, 2018 at 12:53 AM Stanislav
> >>> > >> > > >> Lukyanov <
> >>> > >> > > >>>>>>>>>>>>>>>  stanlukyanov@gmail.com >
> >>> > >> > > >>>>>>>>>>>>>>> wrote:
> >>> > >> > > >>>>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>>>>> Hi Igniters,
> >>> > >> > > >>>>>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>>>>> I’d like to start a discussion about the
> >>> > >> > > >>>> deprecation of
> >>> > >> > > >>>>>>> the
> >>> > >> > > >>>>>>>>>> LOCAL
> >>> > >> > > >>>>>>>>>>>>>> caches.
> >>> > >> > > >>>>>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>>>>> LOCAL caches are an edge-case functionality
> >>> > >> > > >>>>>>>>>>>>>>>> I haven’t done any formal analysis, but from
> >>> my
> >>> > >> > > >>>>>>> experience
> >>> > >> > > >>>>>>>>>> LOCAL
> >>> > >> > > >>>>>>>>>>>>> caches
> >>> > >> > > >>>>>>>>>>>>>>>> are needed very rarely, if ever.
> >>> > >> > > >>>>>>>>>>>>>>>> I think most usages of LOCAL caches I’ve seen
> >>> > >> > > >> were
> >>> > >> > > >>>>>>> misuses:
> >>> > >> > > >>>>>>>>> the
> >>> > >> > > >>>>>>>>>>>> users
> >>> > >> > > >>>>>>>>>>>>>>>> actually needed a simple HashMap, or an actual
> >>> > >> > > >>>>>>> PARTITIONED
> >>> > >> > > >>>>>>>>>> cache.
> >>> > >> > > >>>>>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>>>>> LOCAL caches are easy to implement on top of
> >>> > >> > > >>>>>> PARTITIONED
> >>> > >> > > >>>>>>>>>>>>>>>> If one requires a LOCAL cache (which is itself
> >>> > >> > > >>>>>>>> questionable,
> >>> > >> > > >>>>>>>>> as
> >>> > >> > > >>>>>>>>>>>>>> discussed
> >>> > >> > > >>>>>>>>>>>>>>>> above) it is quite easy to implement one on
> >>> > >> > > >> top of
> >>> > >> > > >>>>>>>>> PARTITIONED
> >>> > >> > > >>>>>>>>>>>> cache.
> >>> > >> > > >>>>>>>>>>>>>>>> A node filter of form `node -> node.id
> >>> > >> > > >>>>>>>>> ().equals(localNodeId)`
> >>> > >> > > >>>>>>>>>> is
> >>> > >> > > >>>>>>>>>>>>>> enough
> >>> > >> > > >>>>>>>>>>>>>>>> to make the cache to be stored on the node
> >>> that
> >>> > >> > > >>>> created
> >>> > >> > > >>>>>>> it.
> >>> > >> > > >>>>>>>>>>>>>>>> Locality of access to the cache (i.e. making
> >>> it
> >>> > >> > > >>>>>>> unavailable
> >>> > >> > > >>>>>>>>>> from
> >>> > >> > > >>>>>>>>>>>>> other
> >>> > >> > > >>>>>>>>>>>>>>>> nodes) can be achieved on the application
> >>> > >> > > >> level.
> >>> > >> > > >>>>>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>>>>> LOCAL caches are hard to maintain
> >>> > >> > > >>>>>>>>>>>>>>>> A quick look at the open issues mentioning
> >>> > >> > > >> “local
> >>> > >> > > >>>>>> cache”
> >>> > >> > > >>>>>>>>>> suggests
> >>> > >> > > >>>>>>>>>>>>> that
> >>> > >> > > >>>>>>>>>>>>>>>> this is a corner case for implementation of
> >>> > >> > > >> many
> >>> > >> > > >>>> Ignite
> >>> > >> > > >>>>>>>>>> features:
> >>> > >> > > >>>>>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>>>>>
> >>> > >> > > >>>>>>  https://issues.apache.org/jira/issues/?jql=text%20~%20%
> >>> > >> > > >>>>>>>>>>>>>>>
> >>> > >> > > >> 22local%20cache%22%20and%20%20project%20%3D%20IGNITE%
> >>> > >> > > >>>>>>>>>>>>>>> 20and%20status%20%3D%20open
> >>> > >> > > >>>>>>>>>>>>>>>> In particular, a recent SO question brought up
> >>> > >> > > >> the
> >>> > >> > > >>>> fact
> >>> > >> > > >>>>>>>> that
> >>> > >> > > >>>>>>>>>>> LOCAL
> >>> > >> > > >>>>>>>>>>>>>> caches
> >>> > >> > > >>>>>>>>>>>>>>>> don’t support native persistence:
> >>> > >> > > >>>>>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>>>>>
> >>> > >> > > >>>>  https://stackoverflow.com/questions/51511892/how-to-
> >>> > >> > > >>>>>>>>>>>>>>>
> >>> > >> > > >> configure-persistent-storage-for-apache-ignite-cache
> >>> > >> > > >>>>>>>>>>>>>>>> Having to ask ourselves “how does it play with
> >>> > >> > > >>>> LOCAL
> >>> > >> > > >>>>>>>> caches”
> >>> > >> > > >>>>>>>>>>> every
> >>> > >> > > >>>>>>>>>>>>> time
> >>> > >> > > >>>>>>>>>>>>>>> we
> >>> > >> > > >>>>>>>>>>>>>>>> write any code in Ignite seems way to much for
> >>> > >> > > >> the
> >>> > >> > > >>>>>>> benefits
> >>> > >> > > >>>>>>>>> we
> >>> > >> > > >>>>>>>>>>> gain
> >>> > >> > > >>>>>>>>>>>>>> from
> >>> > >> > > >>>>>>>>>>>>>>> it.
> >>> > >> > > >>>>>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>>>>> Proposal
> >>> > >> > > >>>>>>>>>>>>>>>> Let’s deprecate LOCAL caches in 2.x and remove
> >>> > >> > > >>>> them in
> >>> > >> > > >>>>>>> 3.0.
> >>> > >> > > >>>>>>>>>>>>>>>> As a part of deprecation let’s do the
> >>> > >> > > >> following:
> >>> > >> > > >>>>>>>>>>>>>>>> - Put @Deprecated on the CacheMode.LOCAL
> >>> > >> > > >>>>>>>>>>>>>>>> - Print a warning every time a LOCAL cache is
> >>> > >> > > >>>> created
> >>> > >> > > >>>>>>>>>>>>>>>> - Remove all mentions of LOCAL caches from
> >>> > >> > > >>>> readme.io,
> >>> > >> > > >>>>>> if
> >>> > >> > > >>>>>>>>> any,
> >>> > >> > > >>>>>>>>>>>> except
> >>> > >> > > >>>>>>>>>>>>>> for
> >>> > >> > > >>>>>>>>>>>>>>>> the page about cache modes
> >>> > >> > > >>>>>>>>>>>>>>>> - On the page about cache modes explain that
> >>> > >> > > >> LOCAL
> >>> > >> > > >>>> is
> >>> > >> > > >>>>>>>>>> deprecated
> >>> > >> > > >>>>>>>>>>>> and
> >>> > >> > > >>>>>>>>>>>>>> can
> >>> > >> > > >>>>>>>>>>>>>>>> be replaced with a PARTITIONED cache with a
> >>> > >> > > >> node
> >>> > >> > > >>>> filter
> >>> > >> > > >>>>>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>>>>> Thanks,
> >>> > >> > > >>>>>>>>>>>>>>>> Stan
> >>> > >> > > >>>>>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>>
> >>> > >> > > >>>>>>>>>>
> >>> > >> > > >>>>>>>>>
> >>> > >> > > >>>>>>>>
> >>> > >> > > >>>>>>>
> >>> > >> > > >>>>>>
> >>> > >> > > >>>>
> >>> > >> > > >>>
> >>> > >> > > >>>
> >>> > >> > > >>> --
> >>> > >> > > >>> Sincerely yours, Ivan Daschinskiy
> >>> > >> > > >>
> >>> > >> > > >
> >>> > >> > > >
> >>> > >> > > > --
> >>> > >> > > > Sincerely yours, Ivan Daschinskiy
> >>> > >> > >
> >>> > >> > >
> >>> > >> >
> >>> > >> > --
> >>> > >> > Sincerely yours, Ivan Daschinskiy
> >>> > >> >
> >>> > >>
> >>> > >
> >>> > >
> >>> > > --
> >>> > > Sincerely yours, Ivan Daschinskiy
> >>> > >
> >>> >
> >>> >
> >>> > --
> >>> > Sincerely yours, Ivan Daschinskiy
> >>>
> >>
> >> --
> >> Sincerely yours, Ivan Daschinskiy
> >
> >
> >
> >
>
>
>
>