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Posted to issues@hive.apache.org by "Shohei Okumiya (Jira)" <ji...@apache.org> on 2026/03/16 03:24:00 UTC

[jira] [Updated] (HIVE-29438) Statistics: inaccurate handling of unknown numNulls/numTrues/numFalses stats

     [ https://issues.apache.org/jira/browse/HIVE-29438?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Shohei Okumiya updated HIVE-29438:
----------------------------------
    Fix Version/s: 4.3.0
       Resolution: Fixed
           Status: Resolved  (was: Patch Available)

Merged. [~konstantinb] Thanks for your contribution!
https://github.com/apache/hive/pull/6294

> Statistics: inaccurate handling of unknown numNulls/numTrues/numFalses stats
> ----------------------------------------------------------------------------
>
>                 Key: HIVE-29438
>                 URL: https://issues.apache.org/jira/browse/HIVE-29438
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Konstantin Bereznyakov
>            Assignee: Konstantin Bereznyakov
>            Priority: Major
>              Labels: pull-request-available
>             Fix For: 4.3.0
>
>         Attachments: HIVE-29438.patch
>
>
>   In some implementations, it can be very expensive to maintain fully accurate column statistics, especially for large tables. The recommended value to use when numNulls/numFalses/numTrues are unknown is -1.
>   However, the statistics code has a few places where it treats "-1" as a literal quantity rather than a sentinel value, leading to inaccurate and sometimes catastrophic estimations (e.g., incorrect join ordering, wrong memory allocation for operators).



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