Prasanth J created HIVE-5921:
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Summary: Better heuristics for worst case statistics estimates for
join, limit and filter operator
Key: HIVE-5921
URL: https://issues.apache.org/jira/browse/HIVE-5921
Project: Hive
Issue Type: Sub-task
Affects Versions: 0.13.0
Reporter: Prasanth J
Assignee: Prasanth J
This is a subtask of HIVE-5369. In worst case (i.e; absence of column
statistics) HIVE-5849 improved the basic statistics with heuristics. But the
heuristics failed to provide better estimates in few cases. For example: FILTER
operator heuristics did not take into account the number of predicates and if
the predicate contains partition column. Also, JOIN estimates were too
aggressive and was not user configurable.
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