[jira] [Resolved] (IMPALA-6113) Skip row groups with predicates on NULL columns

["Gabor Kaszab (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/IMPALA-6113?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Gabor Kaszab resolved IMPALA-6113.
----------------------------------
       Resolution: Fixed
    Fix Version/s: Impala 2.12.0

https://gerrit.cloudera.org/#/c/9140/

> Skip row groups with predicates on NULL columns
> -----------------------------------------------
>
>                 Key: IMPALA-6113
>                 URL: https://issues.apache.org/jira/browse/IMPALA-6113
>             Project: IMPALA
>          Issue Type: Improvement
>          Components: Backend
>    Affects Versions: Impala 2.10.0
>            Reporter: Lars Volker
>            Assignee: Gabor Kaszab
>            Priority: Major
>              Labels: ramp-up
>             Fix For: Impala 2.12.0
>
>
> Column chunks that only contain NULL values don't have their {{min_value}} and {{max_value}} fields populated and as a result we cannot skip row groups based on predicates on such columns. IMPALA-5061 added support to populate the null_count in statistics, allowing us to detect column chunks that only contain NULLs. We should use that information to skip row groups if the predicate allows us to.



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