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Hive >> mail # dev >> Review Request: HIVE-4435: Column stats: Distinct value estimator should use hash functions that are pairwise independent


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Shreepadma Venugopalan 2013-04-29, 20:41
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Re: Review Request: HIVE-4435: Column stats: Distinct value estimator should use hash functions that are pairwise independent

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This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/10841/
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(Updated May 31, 2013, 2:24 a.m.)
Review request for hive, Ashutosh Chauhan and Navis Ryu.
Changes
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Added reviewers.
Description
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Fixes the FM estimator to use hash functions that are pairwise independent.
This addresses bug HIVE-4435.
    https://issues.apache.org/jira/browse/HIVE-4435
Diffs
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  ql/src/java/org/apache/hadoop/hive/ql/udf/generic/NumDistinctValueEstimator.java 69e6f46

Diff: https://reviews.apache.org/r/10841/diff/
Testing
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The estimates are within the expected error after this fix. Tested on TPCH of varying sizes.
Thanks,

Shreepadma Venugopalan