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From Andrey Mashenkov <andrey.mashen...@gmail.com>
Subject Re: Non-collocated distributed SQL Joins across caches over separate cluster groups
Date Wed, 05 Apr 2017 12:24:45 GMT
Sergi,

Does it means that "broken" FairAffinityFunction can lead to wrong SQL
query result?
As we know, using FairAF have no guarantee that same parititions of
different caches can belongs to different nodes in some cases.

On Wed, Apr 5, 2017 at 1:47 PM, Sergi Vladykin <sergi.vladykin@gmail.com>
wrote:

> Hi,
>
> Moreover distributed joins can be executed only between caches with the
> same affinity (same partitions on the same nodes).
>
> Keep in mind that distributed join is already a "last resort" thing and you
> have to prefer collocated joins as much as possible, if you want to achieve
> good performance. Distributed join between different cluster groups will
> make things even worse.
>
> Sergi
>
> 2017-04-05 12:02 GMT+03:00 Christos Erotocritou <christos@gridgain.com>:
>
> > Igniters,
> >
> > Is it correct to assume the following:
> >
> >    - We have an Ignite cluster comprised of 2 cluster groups A & B that
> >    have different caches deployed.
> >    - We use an Ignite client to obtain API access to the whole cluster
> >    and execute a join query that joins data across the 2 caches
> >
> > My understanding is that this is *not possible*, correct?
> >
> > Reading this article [1
> > <https://dzone.com/articles/how-apache-ignite-helped-a-
> large-bank-process-geog-1>]
> > it seems that such cross-cluster-group behaviour is supported with the
> > transactions API and also advised.
> >
> > Any thoughts why the SQL API would not allow this and requires caches to
> > be located on all nodes when the JOIN query is executed?
> >
> > Cheers,
> > Christos
> >
>



-- 
Best regards,
Andrey V. Mashenkov

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