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From Brian O'Neill <b...@alumni.brown.edu>
Subject Re: Dimensional SUM, COUNT, & DISTINCT in C* (replacing Acunu)
Date Wed, 18 Dec 2013 20:30:25 GMT

Thanks for the pointer Alain.

At a quick glance, it looks like people are looking for query time
filtering/aggregation, which will suffice for small data sets.  Hopefully we
might be able to extend that to perform pre-computations as well. (which
would support much larger data sets / volumes)

I¹ll continue the discussion on the issue.

thanks again,
brian


---
Brian O'Neill
Chief Architect
Health Market Science
The Science of Better Results
2700 Horizon Drive € King of Prussia, PA € 19406
M: 215.588.6024 € @boneill42 <http://www.twitter.com/boneill42>   €
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From:  Alain RODRIGUEZ <arodrime@gmail.com>
Reply-To:  <user@cassandra.apache.org>
Date:  Wednesday, December 18, 2013 at 5:13 AM
To:  <user@cassandra.apache.org>
Cc:  "dev@cassandra.apache.org" <dev@cassandra.apache.org>
Subject:  Re: Dimensional SUM, COUNT, & DISTINCT in C* (replacing Acunu)

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 I¹ve 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
> CF¹s)
> 
> 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 <tel:215.588.6024>
> blog: http://brianoneill.blogspot.com/
> twitter: @boneill42




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