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From Robert Metzger <rmetz...@apache.org>
Subject Re: Difference between partition and groupBy
Date Thu, 23 Feb 2017 20:51:46 GMT
Hi Patrick,

I think (but I'm not 100% sure) its not a difference in what the engine
does in the end, its more of an API thing. When you are grouping, you can
perform operations such as reducing afterwards.
On a partitioned dataset, you can do stuff like processing each partition
in parallel, or sort them.

The parallelism is independent of the partitioning or grouping. Usually
there are more partitions than parallel instances, so each instance will
take care of multiple partitions.



On Thu, Feb 23, 2017 at 6:16 PM, Patrick Brunmayr <jay@kpibench.com> wrote:

> What is the basic difference between partitioning datasets by key or
> grouping them by key ?
>
> Does it make a difference in terms of paralellism ?
>
> Thx
>

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