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From Igor Sapego <isap...@apache.org>
Subject Re: Best Effort Affinity for thin clients
Date Mon, 04 Feb 2019 12:06:03 GMT
Vladimir,

So correct me if I'm wrong, what you propose is to avoid mentioning
of cache groups, and use instead of "cache group" term something like
"distribution"? Or do you propose some changes in protocol? If so, can
you briefly explain, what kind of changes they are?

Best Regards,
Igor


On Mon, Feb 4, 2019 at 1:13 PM Vladimir Ozerov <vozerov@gridgain.com> wrote:

> Igor,
>
> Yes, cache groups are public API. However, we try to avoid new APIs
> depending on them.
> The main point from my side is that “similar cache group” can be easily
> generalized to “similar distribution”. This way we avoid cache groups on
> protocol level at virtually no cost.
>
> Vladimir.
>
> пн, 4 февр. 2019 г. в 12:48, Igor Sapego <isapego@apache.org>:
>
> > Guys,
> >
> > Can you explain why do we want to avoid Cache groups in protocol?
> >
> > If it's about simplicity of the protocol, then removing cache groups will
> > not help much with it - we will still need to include "knownCacheIds"
> > field in request and "cachesWithTheSamePartitioning" field in response.
> > And also, since when do Ignite prefers simplicity over performance?
> >
> > If it's about not wanting to show internals of Ignite then it sounds like
> > a very weak argument to me, since Cache Groups is a public thing [1].
> >
> > [1] - https://apacheignite.readme.io/docs/cache-groups
> >
> > Best Regards,
> > Igor
> >
> >
> > On Mon, Feb 4, 2019 at 11:47 AM Vladimir Ozerov <vozerov@gridgain.com>
> > wrote:
> >
> > > Pavel, Igor,
> > >
> > > This is not very accurate to say that this will not save memory. In
> > > practice we observed a number of OOME issues on the server-side due to
> > many
> > > caches and it was one of motivations for cache groups (another one disk
> > > access optimizations). On the other hand, I agree that we'd better to
> > avoid
> > > cache groups in the protocol because this is internal implementation
> > detail
> > > which is likely (I hope so) to be changed in future.
> > >
> > > So I have another proposal - let's track caches with the same affinity
> > > distribution instead. That is, normally most of PARTITIONED caches will
> > > have very few variants of configuration: it will be Rendezvous affinity
> > > function, most likely with default partition number and with 1-2
> backups
> > at
> > > most. So when affinity distribution for specific cache is requested, we
> > can
> > > append to the response *list of caches with the same distribution*.
> I.e.:
> > >
> > > class AffinityResponse {
> > >     Object distribution;    // Actual distribution
> > >     List<Integer> cacheIds; // Caches with similar distribution
> > > }
> > >
> > > Makes sense?
> > >
> > > On Sun, Feb 3, 2019 at 8:31 PM Pavel Tupitsyn <ptupitsyn@apache.org>
> > > wrote:
> > >
> > > > Igor, I have a feeling that we should omit Cache Group stuff from the
> > > > protocol.
> > > > It is a rare use case and even then dealing with them on client
> barely
> > > > saves some memory.
> > > >
> > > > We can keep it simple and have partition map per cacheId. Thoughts?
> > > >
> > > > On Fri, Feb 1, 2019 at 6:49 PM Igor Sapego <isapego@apache.org>
> wrote:
> > > >
> > > > > Guys, I've updated the proposal once again [1], so please,
> > > > > take a look and let me know what you think.
> > > > >
> > > > > [1] -
> > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/IGNITE/IEP-23%3A+Best+Effort+Affinity+for+thin+clients
> > > > >
> > > > > Best Regards,
> > > > > Igor
> > > > >
> > > > >
> > > > > On Thu, Jan 17, 2019 at 1:05 PM Igor Sapego <isapego@apache.org>
> > > wrote:
> > > > >
> > > > > > Yeah, I'll add it.
> > > > > >
> > > > > > Best Regards,
> > > > > > Igor
> > > > > >
> > > > > >
> > > > > > On Wed, Jan 16, 2019 at 11:08 PM Pavel Tupitsyn <
> > > ptupitsyn@apache.org>
> > > > > > wrote:
> > > > > >
> > > > > >> >  to every server
> > > > > >> I did not think of this issue. Now I agree with your approach.
> > > > > >> Can you please add an explanation of this to the IEP?
> > > > > >>
> > > > > >> Thanks!
> > > > > >>
> > > > > >> On Wed, Jan 16, 2019 at 2:53 PM Igor Sapego <isapego@apache.org
> >
> > > > wrote:
> > > > > >>
> > > > > >> > Pavel,
> > > > > >> >
> > > > > >> > Yeah, it makes sense, but to me it seems that this
approach
> can
> > > lead
> > > > > >> > to more complicated client logic, as it will require
to make
> > > > > additional
> > > > > >> > call
> > > > > >> > to every server, that reports affinity topology change.
> > > > > >> >
> > > > > >> > Guys, WDYT?
> > > > > >> >
> > > > > >> > Best Regards,
> > > > > >> > Igor
> > > > > >> >
> > > > > >> >
> > > > > >> > On Tue, Jan 15, 2019 at 10:59 PM Pavel Tupitsyn <
> > > > ptupitsyn@apache.org
> > > > > >
> > > > > >> > wrote:
> > > > > >> >
> > > > > >> > > Igor,
> > > > > >> > >
> > > > > >> > > >  It is proposed to add flag to every response,
that shows
> > > > whether
> > > > > >> the
> > > > > >> > > Affinity Topology Version of the cluster has changed
since
> the
> > > > last
> > > > > >> > request
> > > > > >> > > from the client.
> > > > > >> > > I propose to keep this flag. So no need for periodic
checks.
> > > Makes
> > > > > >> sense?
> > > > > >> > >
> > > > > >> > > On Tue, Jan 15, 2019 at 4:45 PM Igor Sapego <
> > isapego@apache.org
> > > >
> > > > > >> wrote:
> > > > > >> > >
> > > > > >> > > > Pavel,
> > > > > >> > > >
> > > > > >> > > > This will require from client to send this
new request
> > > > > periodically,
> > > > > >> > I'm
> > > > > >> > > > not
> > > > > >> > > > sure this will make clients simpler. Anyway,
let's discuss
> > it.
> > > > > >> > > >
> > > > > >> > > > Vladimir,
> > > > > >> > > >
> > > > > >> > > > With current proposal, we will have affinity
info in
> message
> > > > > header.
> > > > > >> > > >
> > > > > >> > > > Best Regards,
> > > > > >> > > > Igor
> > > > > >> > > >
> > > > > >> > > >
> > > > > >> > > > On Tue, Jan 15, 2019 at 11:01 AM Vladimir
Ozerov <
> > > > > >> vozerov@gridgain.com
> > > > > >> > >
> > > > > >> > > > wrote:
> > > > > >> > > >
> > > > > >> > > > > Igor,
> > > > > >> > > > >
> > > > > >> > > > > I think that "Cache Partitions Request"
should contain
> > > > affinity
> > > > > >> > > topology
> > > > > >> > > > > version. Otherwise we do not know what
distribution is
> > > > returned
> > > > > -
> > > > > >> the
> > > > > >> > > one
> > > > > >> > > > > we expected, or some newer one. The
latter may happen in
> > > case
> > > > > >> > topology
> > > > > >> > > > > changed or late affinity assignment
happened between
> > server
> > > > > >> response
> > > > > >> > > and
> > > > > >> > > > > subsequent client partitions request.
> > > > > >> > > > >
> > > > > >> > > > > Vladimir.
> > > > > >> > > > >
> > > > > >> > > > > On Mon, Jan 14, 2019 at 6:08 PM Igor
Sapego <
> > > > isapego@apache.org
> > > > > >
> > > > > >> > > wrote:
> > > > > >> > > > >
> > > > > >> > > > > > Hello guys,
> > > > > >> > > > > >
> > > > > >> > > > > > I've updated IEP page [1] describing
proposed solution
> > in
> > > > more
> > > > > >> > > details
> > > > > >> > > > > and
> > > > > >> > > > > > proposing some changes for a protocol.
> > > > > >> > > > > >
> > > > > >> > > > > > Please, take a look and let me
know what you think.
> > > > > >> > > > > >
> > > > > >> > > > > > [1] -
> > > > > >> > > > > >
> > > > > >> > > > > >
> > > > > >> > > > >
> > > > > >> > > >
> > > > > >> > >
> > > > > >> >
> > > > > >>
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/IGNITE/IEP-23%3A+Best+Effort+Affinity+for+thin+clients
> > > > > >> > > > > >
> > > > > >> > > > > > Best Regards,
> > > > > >> > > > > > Igor
> > > > > >> > > > > >
> > > > > >> > > > > >
> > > > > >> > > > > > On Tue, Jun 19, 2018 at 11:54 AM
Vladimir Ozerov <
> > > > > >> > > vozerov@gridgain.com
> > > > > >> > > > >
> > > > > >> > > > > > wrote:
> > > > > >> > > > > >
> > > > > >> > > > > > > Denis,
> > > > > >> > > > > > >
> > > > > >> > > > > > > Yes, in principle we can extend
it. We are going to
> > > > > implement
> > > > > >> it
> > > > > >> > in
> > > > > >> > > > > > > subsequent phases of this
IEP.
> > > > > >> > > > > > >
> > > > > >> > > > > > > On Tue, Jun 19, 2018 at 4:30
AM, Dmitriy Setrakyan <
> > > > > >> > > > > > dsetrakyan@apache.org>
> > > > > >> > > > > > > wrote:
> > > > > >> > > > > > >
> > > > > >> > > > > > > > On Mon, Jun 18, 2018
at 11:07 AM, Denis Magda <
> > > > > >> > dmagda@apache.org
> > > > > >> > > >
> > > > > >> > > > > > wrote:
> > > > > >> > > > > > > >
> > > > > >> > > > > > > > > Folks,
> > > > > >> > > > > > > > >
> > > > > >> > > > > > > > > Feel that this functionality
can be extended to
> > the
> > > > > >> automatic
> > > > > >> > > > > > > reconnect,
> > > > > >> > > > > > > > > can't it? Presently
we require to provide a
> static
> > > > list
> > > > > of
> > > > > >> > IPs
> > > > > >> > > to
> > > > > >> > > > > be
> > > > > >> > > > > > > used
> > > > > >> > > > > > > > > at a reconnect time.
By having a partition map
> of
> > > all
> > > > > the
> > > > > >> > > nodes,
> > > > > >> > > > > the
> > > > > >> > > > > > > thin
> > > > > >> > > > > > > > > client should be
able to automate this piece.
> > > > > >> > > > > > > > >
> > > > > >> > > > > > > >
> > > > > >> > > > > > > > Not sure if static IP
list can be avoided. What
> Igor
> > > is
> > > > > >> > > suggesting
> > > > > >> > > > is
> > > > > >> > > > > > > that
> > > > > >> > > > > > > > we try to pick the best
node out of the static IP
> > > list.
> > > > > >> > > > > > > >
> > > > > >> > > > > > > > D.
> > > > > >> > > > > > > >
> > > > > >> > > > > > >
> > > > > >> > > > > >
> > > > > >> > > > >
> > > > > >> > > >
> > > > > >> > >
> > > > > >> >
> > > > > >>
> > > > > >
> > > > >
> > > >
> > >
> >
>

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