Details
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Improvement
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Status: Patch Available
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Minor
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Resolution: Unresolved
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None
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None
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Description
Queries for fetching results which have lastly "order by" clause make final MR run with single reducer, which can be too much. For example,
select value, sum(key) as sum from src group by value order by sum;
If number of reducer is reasonable, multiple result files could be merged into single sorted stream in the fetcher level.