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From Tyler Hobbs <ty...@datastax.com>
Subject Re: Proper use of COUNT
Date Tue, 19 Apr 2016 16:04:24 GMT
On Tue, Apr 19, 2016 at 9:51 AM, Jack Krupansky <jack.krupansky@gmail.com>
wrote:

>
> 1. Another clarification: All of the aggregate functions, AVG, SUM, MIN,
> MAX are in exactly the same boat as COUNT, right?
>

Yes.


>
> 2. Is the paging for COUNT, et al, done within the coordinator node?
>

Yes.


>
> 3. Does dedupe on the coordinator node consume memory proportional to the
> number of rows on all nodes? I mean, you can't dedupe using only partition
> keys of the coordinator node, right? What I'm wondering is if the usability
> of COUNT (et al) is memory limited as well as time.
>

Deduping (i.e. normal conflict resolution) happens per-page, so in the
worst case the memory requirements for the coordinator are RF * page size.




-- 
Tyler Hobbs
DataStax <http://datastax.com/>

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