[jira] [Updated] (HIVE-9645) Constant folding case NULL equality

["Ashutosh Chauhan (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HIVE-9645?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Ashutosh Chauhan updated HIVE-9645:
-----------------------------------
    Attachment: HIVE-9645.patch

Fold expression involving nulls now.

> Constant folding case NULL equality
> -----------------------------------
>
>                 Key: HIVE-9645
>                 URL: https://issues.apache.org/jira/browse/HIVE-9645
>             Project: Hive
>          Issue Type: Bug
>          Components: Logical Optimizer
>    Affects Versions: 1.2.0
>            Reporter: Gopal V
>         Attachments: HIVE-9645.patch
>
>
> Hive logical optimizer does not follow the Null scan codepath when encountering a NULL = 1;
> NULL = 1 is not evaluated as false in the constant propogation implementation.
> {code}
> hive> explain select count(1) from store_sales where null=1;
> ...
>              TableScan
>                   alias: store_sales
>                   filterExpr: (null = 1) (type: boolean)
>                   Statistics: Num rows: 550076554 Data size: 49570324480 Basic stats: COMPLETE Column stats: COMPLETE
>                   Filter Operator
>                     predicate: (null = 1) (type: boolean)
>                     Statistics: Num rows: 275038277 Data size: 0 Basic stats: PARTIAL Column stats: COMPLETE
> {code}



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