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https://issues.apache.org/jira/browse/IMPALA-9358?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Work on IMPALA-9358 started by Kurt Deschler.
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> Query slowdown with inline views and hundreds of columns
> --------------------------------------------------------
>
>                 Key: IMPALA-9358
>                 URL: https://issues.apache.org/jira/browse/IMPALA-9358
>             Project: IMPALA
>          Issue Type: Bug
>          Components: Frontend
>    Affects Versions: Impala 3.2.0
>            Reporter: Kurt Deschler
>            Assignee: Kurt Deschler
>            Priority: Major
>             Fix For: Impala 3.4.0
>
>
> IMPALA-8386 introduced an expensive precondition check using the function 
> ExprSubstitutionMap.checkComposedFrom(). This check has significant 
> performance impact on statements that contain inline views with hundreds of 
> columns. This check needs to be made more efficient to avoid exponential 
> slowdowns with many columns.



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