Details
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Improvement
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Status: Closed
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Major
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Resolution: Fixed
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None
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None
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Improved shuffle so that all fetched map-outputs are kept in-memory before being merged by stalling the shuffle so that the in-memory merge executes and frees up memory for the shuffle.
Description
This is intended to be a meta-issue to track various improvements to shuffle/merge in the reducer.
Attachments
Attachments
Issue Links
- depends upon
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HADOOP-2095 Reducer failed due to Out ofMemory
- Closed
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HADOOP-3365 SequenceFile.Sorter.MergeQueue.next does an unnecessary copy of the key
- Closed
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HADOOP-3297 The way in which ReduceTask/TaskTracker gets completion events during shuffle can be improved
- Closed