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https://issues.apache.org/jira/browse/TEZ-3430?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Ming Ma updated TEZ-3430:
-------------------------
Attachment: TEZ-3430.patch
Here is the draft patch. It adds a new option sortSplitsEnabled to
configuration.
> Make split sorting optional
> ---------------------------
>
> Key: TEZ-3430
> URL: https://issues.apache.org/jira/browse/TEZ-3430
> Project: Apache Tez
> Issue Type: Bug
> Reporter: Ming Ma
> Attachments: TEZ-3430.patch
>
>
> The fair routing design in TEZ-3209 addresses the skewed partitions where one
> partition could be much larger than the others. But to simplify the stats
> tracking, it assumes a given partition's data is distributed evenly to some
> degree across source tasks so that it can group consecutive source tasks
> together.
> However, this assumption is invalid given {{MRInputHelpers}}'s
> generateNewSplits and generateOldSplits sort the splits by size, thus the
> data size in the beginning of source task range is bigger than that of at the
> end.
> {noformat}
> Arrays.sort(splits, new InputSplitComparator());
> {noformat}
> One way to fix this is to have fair routing track not only the aggregated
> size of each partition, but also the size of each partition of each source
> task. But that will significantly increase the memory footprint.
> Alternatively, it can skip the sorting above. Test results for TEZ-3209 show
> that jobs can finish 30% faster, given the source tasks output size is more
> balanced.
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