[jira] [Created] (HIVE-5921) Better heuristics for worst case statistics estimates for join, limit and filter operator

["Prasanth J (JIRA)" <ji...@apache.org>]

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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