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Ashutosh Chauhan commented on HIVE-4435: ---------------------------------------- Following tests failed: * compute_stats_double.q * compute_stats_long.q * compute_stats_string.q I am assuming since we have better estimates now, we just need to update .q.out files for these. Can you verify and if so can you update the patch with it? > Column stats: Distinct value estimator should use hash functions that are > pairwise independent > ---------------------------------------------------------------------------------------------- > > Key: HIVE-4435 > URL: https://issues.apache.org/jira/browse/HIVE-4435 > Project: Hive > Issue Type: Bug > Components: Statistics > Affects Versions: 0.10.0 > Reporter: Shreepadma Venugopalan > Assignee: Shreepadma Venugopalan > Attachments: chart_1(1).png, HIVE-4435.1.patch > > > The current implementation of Flajolet-Martin estimator to estimate the > number of distinct values doesn't use hash functions that are pairwise > independent. This is problematic because the input values don't distribute > uniformly. When run on large TPC-H data sets, this leads to a huge > discrepancy for primary key columns. Primary key columns are typically a > monotonically increasing sequence. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira