GitHub user ConeyLiu opened a pull request:
https://github.com/apache/spark/pull/19317
[SPARK-22098][CORE] Add new method aggregateByKeyLocally in RDD
## What changes were proposed in this pull request?
https://issues.apache.org/jira/browse/SPARK-22096
NaiveBayes currently takes aggreateByKey followed by a collect to calculate
frequency for each feature/label. We can implement a new function
'aggregateByKeyLocally' in RDD that merges locally on each mapper before
sending results to a reducer to save one stage.
We tested on NaiveBayes and see ~20% performance gain with these changes.
This is a subtask of our improvement.
## How was this patch tested?
New UT.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/ConeyLiu/spark aggregatebykeylocally
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/19317.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #19317
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commit 73a85dc5963ac46f181a9499deabb18da4ccc308
Author: Xianyang Liu <[email protected]>
Date: 2017-08-31T05:16:09Z
add new method 'aggregateByKeyLocally'
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