[jira] [Resolved] (IMPALA-8205) Illegal statistics for numFalse and numTrue

["Tim Armstrong (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/IMPALA-8205?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Tim Armstrong resolved IMPALA-8205.
-----------------------------------
    Fix Version/s: Impala 4.0
       Resolution: Fixed

> Illegal statistics for numFalse and numTrue
> -------------------------------------------
>
>                 Key: IMPALA-8205
>                 URL: https://issues.apache.org/jira/browse/IMPALA-8205
>             Project: IMPALA
>          Issue Type: Bug
>          Components: Catalog
>            Reporter: wuchang
>            Assignee: wuchang
>            Priority: Major
>              Labels: impala, numFalse, numTrue, statistics
>             Fix For: Impala 4.0
>
>
> When impala compute statistics, it set *numFalse = -1* and *numTrue = 1* when the statistic is missing;
> *-1* for *numFalse* will corrupt some query engine like Presto and there already exists some PR report and hotfix it : [presto-11859|https://github.com/prestodb/presto/pull/11859]
> *1* for *numTrue* is also unreasonable because we are not sure whether it indicates the real numTrue statistics or a missing statistics;
> Also, previously , the *nullCount* also use -1 to indicate its absence which also caused problem for Presto. Presto has to add a hotfix for it([presto-11549|https://github.com/prestodb/presto/pull/11549]) . But it is a fortunate that impala has fixed this bug;
> It is necessary to set to null when these statistics are absent instead of -1 and 1.



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