Details
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Bug
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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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None
Description
A join B on A.x = B.y
can be transformed to
(A where x is not null) join (B where y is not null) on A.x = B.y
Apart from avoiding shuffling null keyed rows it also avoids issues with reduce-side skew when there are a lot of null values in the data.
Thanks to gopalv for the analysis and coming up with the solution.
Attachments
Attachments
Issue Links
- supercedes
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HIVE-7151 NULL keys should not be shuffled for inner equi joins
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- Resolved
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