[infinispan-dev] Design change in Infinispan Query

[Emmanuel Bernard]

On 07 Mar 2014, at 16:21, Sanne Grinovero <sanne at infinispan.org> wrote:
> 
>> Is it possible to use an index for x-cache joins with linear index update time and query?
> 
> Index update cost is not linear but LogN: approximates to a constant
> cost. And we could cut this constant by 4 orders of magnitude if only
> I could safely differentiate between a put of a new entry vs. an
> update -> something which we'll need to brainstorm about.
> 
> Query time is also significantly sub-linear in practice, but specifics
> will vary on the query type.
> 
> Yes you could use indexes to improve x-cache joins, but you'll need an
> additional engine to coordinate that correctly, not least to manage
> data size buffers; essentially I think you'd need Teiid.
> 

I think Mircea means implementing joins across different caches if the foreign key is indexed.

It would basically require N index seek (N being the number of fk value on your left hand side) per join and some aggregation engine to link the elements matching from the two side.
So N^M

M= # of joins
N= # of distinct FK involved

Does that reasoning sound right?
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