Description
Currently we can merge 2-way joins into n-way joins when the joins are executed over the same column.
In turn, CBO might produce plans containing cartesian products if the join columns are constant values; after HIVE-12543 went in, this is rather common, as those constant columns are correctly pruned. However, currently we do not merge a cartesian product with two inputs into a cartesian product with multiple inputs, which could result in performance loss.
Attachments
Attachments
Issue Links
- relates to
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HIVE-12543 Disable Hive ConstantPropagate optimizer when CBO has optimized the plan
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- Closed
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- links to
