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Type:
Sub-task
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Status: In Progress
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Priority:
Major
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Resolution: Unresolved
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Affects Version/s: 3.0.0-alpha1
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Fix Version/s: None
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Component/s: applicationmaster, mrv2, tasktracker
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Labels:None
MapTasks need to know whether or not they should start node-level combiner agaist outputs of mapper on their node.
The new umbilical RPC, getAggregationTargets(), is used to get outputs to be aggregated on the node. The definition as follows:
AggregationTarget getAggregationTargets(TaskAttemptID aggregator) throws IOException;
AggregationTarget is a abstraction class of array of TaskAttemptID to be aggregated.