Details
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Improvement
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Resolution: Unresolved
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Major - P3
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Query Optimization
Description
In many cases of MR, people emit 1 key and usually have an index on it.
But few people actually think about sorting, even though it can greatly improve performance.
We can try to automate this for simple cases:
- run the map once on a single doc with a special emit method
- if emitted value is simple, try to match corresponding field in the doc
- if the field has an index, use that index, otherwise maybe log a line advising index