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From Alain RODRIGUEZ <arodr...@gmail.com>
Subject Re: Dimensional SUM, COUNT, & DISTINCT in C* (replacing Acunu)
Date Wed, 18 Dec 2013 10:13:09 GMT
Hi, this would indeed be much appreciated by a lot of people.

There is this issue, existing about this subject

 https://issues.apache.org/jira/browse/CASSANDRA-4914

Maybe could you help commiters there.

Hope this will be usefull to you.

Please let us know when you find a way to do these operations.

Cheers.


2013/12/18 Brian O'Neill <bone@alumni.brown.edu>

> We are seeking to replace Acunu in our technology stack / platform.  It is
> the only component in our stack that is not open source.
>
> In preparation, over the last few weeks I’ve migrated Virgil to CQL.   The
> vision is that Virgil could receive a REST request to upsert/delete data
> (hierarchical JSON to support collections).  Virgil would lookup the
> dimensions/aggregations for that table, add the key to the pertinent
> dimensional tables (e.g. DISTINCT), incorporate values into aggregations
> (e.g. SUMs) and increment/decrement relevant counters (COUNT).  (using
> additional CF’s)
>
> This seems straight-forward, but appears to require a read-before-write.
>  (e.g. read the current value of a SUM, incorporate the new value, then use
> the lightweight transactions of C* 2.0 to conditionally update the value.)
>
> Before I go down this path, I was wondering if anyone is designing/working
> on the same, perhaps at a lower level?  (CQL?)
>
> Is there any intent to support aggregations/filters (COUNT, SUM, DISTINCT,
> etc) at the CQL level?  If so, is there a preliminary design?
>
> I can see a lower-level approach, which would leverage the commit logs
> (and mem/sstables) and perform the aggregation during read-operations (and
> flush/compaction).
>
> thoughts?  i'm open to all ideas.
>
> -brian
> --
> Brian ONeill
> Chief Architect, Health Market Science (http://healthmarketscience.com)
> mobile:215.588.6024
> blog: http://brianoneill.blogspot.com/
> twitter: @boneill42
>

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