Ilya, looks like there is a misunderstanding.
We don't start near cache on a subset of server nodes. Let me explain again.
Consider the following code, executed on any node (client or server - does
not matter):
ignite.createCache(new CacheConfiguration("c").setNearConfiguration(new
NearCacheConfiguration()));
As a result, cache "c" is started on all server nodes, and corresponding
near cache is started on all server nodes,
with the same config, eviction policy, and so on.
Now, what do we do with .NET near cache in this situation?
1. Start .NET near cache as well on server nodes, always.
2. Introduce a config flag, and start .NET near cache only when the flag is
set
The problem with option (1) is that it changes the behavior of existing
applications,
increasing overhead for cache operations and increasing memory usage.
As a user, I don't want some new features to be force-enabled on me
silently in a new product version.
That is why an opt-in config flag is required.
Does this make sense?
On Tue, Feb 18, 2020 at 6:42 PM Ilya Kasnacheev <ilya.kasnach...@gmail.com>
wrote:
> Hello!
>
> I'm not sure that we can/want to create near cache on a subset of server
> nodes.
>
> If this is indeed possible, I would decouple that from .Net and introduce
> as a separate feature.
>
> Ideally we should be able to start or stop near cache on any node, server
> or client, and this should be the same cache for all platforms (including
> Java). WDYT?
>
> Regards,
> --
> Ilya Kasnacheev
>
>
> вт, 18 февр. 2020 г. в 17:31, Pavel Tupitsyn <ptupit...@apache.org>:
>
> > Ilya, as noted above:
> >
> > > There are 2 kinds of Near Caches:
> > > - On client nodes: created per-node by calling ignite.CreateNearCache
> > > - On server nodes: created on all server nodes if
> > CacheConfiguration.NearCacheConfiguration is not null
> > >
> > > When user says ignite.CreateCache(new CacheConfiguration
> > {NearCacheConfiguration = ...}),
> > > the whole config is sent to all server nodes, and .NET-specific flag
> has
> > to be included somehow.
> >
> >
> >
> > On Tue, Feb 18, 2020 at 5:10 PM Ilya Kasnacheev <
> ilya.kasnach...@gmail.com
> > >
> > wrote:
> >
> > > Hello!
> > >
> > > Why would it waste additional memory? All nodes are also Java nodes so
> > they
> > > will start near caches all right.
> > >
> > > Don't we have near cache start-up on per-node basis for clients,
> anyway?
> > >
> > > I'm not convinced why we need this flag. I have to admit my
> understanding
> > > of near caches is limited.
> > >
> > > Regards,
> > > --
> > > Ilya Kasnacheev
> > >
> > >
> > > вт, 18 февр. 2020 г. в 16:56, Pavel Tupitsyn <ptupit...@apache.org>:
> > >
> > > > Ilya, Aleksandr,
> > > >
> > > > The flag is called platformNearCacheEnabled, my idea is to have just
> > one
> > > > flag for all platforms.
> > > >
> > > > If some platform is present on the given node (.NET, C++) and it
> > supports
> > > > native near caching,
> > > > then the flag is honored, otherwise it is ignored. We should not
> throw
> > > > exceptions,
> > > > because mixed clusters are possible (.NET nodes along with Java
> nodes).
> > > >
> > > > > Why would enabling it affect mixed`clusters?
> > > > Initially the idea was to enable .NET near cache whenever
> > > > NearCacheConfiguration is present.
> > > > If we assume .NET-only clusters, it makes sense: existing code will
> > work
> > > > faster automatically.
> > > >
> > > > Mixed cluster is just one of the possible use cases when this may be
> a
> > > bad
> > > > idea,
> > > > e.g. users have enabled near caching to speed up their Java-based
> > > > computations,
> > > > and .NET nodes are used for something else, wasting memory on near
> > > caching
> > > > unnecessarily.
> > > >
> > > > On ue, Feb 18, 2020 at 4:30 PM Aleksandr Shapkin <lexw...@gmail.com
> >
> > > > wrote:
> > > >
> > > > > Pavel,
> > > > >
> > > > >
> > > > >
> > > > > I think it’s ok to add a new flag.
> > > > >
> > > > > Though we may change a name to something like
> > > > #usePlatformCacheIfAvailable
> > > > >
> > > > >
> > > > >
> > > > > But it may vary depending on the implementation, i.e.
> > > > >
> > > > > should we throw an error if there is no native cache
> > > > >
> > > > > available for a platform or just ignore the configuration.
> > > > >
> > > > > вт, 18 февр. 2020 г. в 15:05, Pavel Tupitsyn <ptupit...@apache.org
> >:
> > > > >
> > > > > > Igor,
> > > > > >
> > > > > > The problem is - we need to pass this flag around the cluster`for
> > > > Server
> > > > > > Near Caches,
> > > > > > so that .NET near caches are started accordingly.
> > > > > >
> > > > > > There are 2 kinds of Near Caches:
> > > > > > - On client nodes: created on every client node separately by
> > calling
> > > > > > ignite.CreateNearCache
> > > > > > - On server nodes: created on all server nodes if
> > > > > > CacheConfiguration.NearCacheConfiguration is set
> > > > > >
> > > > > > When user says ignite.CreateCache(new CacheConfiguration
> > > > > > {NearCacheConfiguration = ...}),
> > > > > > the whole config is sent 4o all server nodes, and .NET-specific
> > flag
> > > > has
> > > > > to
> > > > > > be included somehow.
> > > > > >
> > > > > > On Tue, Feb 18, 2020 at 2:59 PM Igor Sapego <isap...@apache.org>
> > > > wrote:
> > > > > >
> > > > > > > Do you suggest to introduce it in general configuration? Why
> not
> > > > > > introduce
> > > > > > > it only on platform side? Is there any .NET-specific
> > configuration?
> > > > > > >
> > > > > > > Best Regards,
> > > > > > > Igo2
> > > > > > >
> > > > > > >
> > > > > > > On Tue, Feb 18, 2020 at 1:10 AM Pavel Tupitsyn <
> > > ptupit...@apache.org
> > > > >
> > > > > > > wrote:
> > > > > > >
> > > > > > > > Igniters,
> > > > > > > >
> > > > > > > > I'm working on .NET Near Cache feature [1]
> > > > > > > > (storing deserialized cache entries in CLR memory to improve
> > > > > > > performance).
> > > > > > > >
> > > > > > > > Implementation is based on Java near cache, with some
> callbacks
> > > to
> > > > > .NET
> > > > > > > > side
> > > > > > > > for updating and invalidating cached entries.
> ~ > > > > > >
> > > > > > > > However, I'd like to make this feature optional: enabling
> Java
> > > near
> > > > > > cache
> > > > > > > > should not
> > > > > > > > always enable .NET near cache - some users may have mixed
> > > clusters,
> > > > > > etc.
> > > > > > > >
> > > > > > > > Therefore I'm adding
> > > > NearCacheConfiguration#platformNearCacheEnabled
> > > > > > > > boolean flag.
> > > > > > > > Are there any objections or better ideas to configure this
> > > > behavior?
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > > Pavel
> > > > > > > >
> > > > > > > > [1] https://issues.apache.org/jira/browse/IGNITE-12691
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > > >
> > > > > --
> > > > > Alex.
> > > > >
> > > >
> > >
> >
>
