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From Jason Heo <jason.heo....@gmail.com>
Subject Any plans for "Aggregation Push down" or integrating Impala + Kudu more tightly?
Date Thu, 29 Jun 2017 09:52:26 GMT
Hi,

Q1.

After reading Druid vs Kudu
<http://druid.io/docs/latest/comparisons/druid-vs-kudu.html>, I wondered
Druid has aggregation push down.

*Druid includes its own query layer that allows it to push down
> aggregations and computations directly to data nodes for faster query
> processing. *


If I understand "Aggregation Push down" correctly, it seems that partial
aggregation is done by data node side, so that only small amount of result
set can be transferred to a client which could lead to great performance
gain. (Am I right?)

So I wanted to know if Apache Kudu has a plan for Aggregation push down
scan feature (Or already has it)

Q2.

One thing that I concern when using Impala+Kudu is that all matching rows
should transferred to impala process from kudu tserver. Usually Impala and
Kudu tserver run on same node. So It would be happy If Impala can read Kudu
Tablet directly. Any plan for this kind of features?

How-to: Use Impala and Kudu Together for Analytic Workloads
<https://blog.cloudera.com/blog/2016/04/how-to-use-impala-and-kudu-together-for-analytic-workloads/>
says that:

*we intend to implement the Apache Arrow in-memory data format and to share
> memory between Kudu and Impala, which we expect will help with performance
> and resource usage.*
>

What does "share memory between Kudu and Impala"? Does this already
implemented?

Thanks

Regards,

Jason

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