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https://issues.apache.org/jira/browse/CASSANDRA-8826?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14367281#comment-14367281
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Sylvain Lebresne commented on CASSANDRA-8826:
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Maybe I can be a bit more precise cause I'm not ever sure we fundamentally
disagree. If you're talking about optimizing aggregates over a single
partition, even a reasonably large one, then I'm fine with that in principle.
But to me, "distributed aggregates" refers to distributing aggregates over
large quantity of data over many nodes _à la_ map-reduce. That's not
particularly real time in my book btw and I maintain that imo that's exactly
what Spark/hadoop are about and there is no point in reinventing that wheel.
Now, if we are talking about single partition aggregates, then the only
relation with this ticket I can see is to push the aggregate on replicas to
save cross-node traffics. We know it's not that that easy for CL > CL.ONE, and
for CL.ONE, I think it's fine to assume that clients do token aware routing, at
which point we already do no transfer data over the wire (and CASSANDRA-7168
will indeed help improve higher CL quite a bit, even without any change to the
current implementation). And I'm just not sure it's worth putting too much
effort short term to optimize the "CL.ONE but no token-aware routing" case.
> Distributed aggregates
> ----------------------
>
> Key: CASSANDRA-8826
> URL: https://issues.apache.org/jira/browse/CASSANDRA-8826
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Robert Stupp
> Priority: Minor
>
> Aggregations have been implemented in CASSANDRA-4914.
> All calculation is performed on the coordinator. This means, that all data is
> pulled by the coordinator and processed there.
> This ticket's about to distribute aggregates to make them more efficient.
> Currently some related tickets (esp. CASSANDRA-8099) are currently in
> progress - we should wait for them to land before talking about
> implementation.
> Another playgrounds (not covered by this ticket), that might be related is
> about _distributed filtering_.
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