[jira] [Assigned] (HIVE-20881) Constant propagation oversimplifies projections

["Zoltan Haindrich (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HIVE-20881?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Zoltan Haindrich reassigned HIVE-20881:
---------------------------------------


> Constant propagation oversimplifies projections
> -----------------------------------------------
>
>                 Key: HIVE-20881
>                 URL: https://issues.apache.org/jira/browse/HIVE-20881
>             Project: Hive
>          Issue Type: Bug
>            Reporter: Zoltan Haindrich
>            Assignee: Zoltan Haindrich
>            Priority: Major
>
> {code:java}
> create table cx2(bool1 boolean);
> insert into cx2 values (true),(false),(null);
> set hive.cbo.enable=true;
> select bool1 IS TRUE OR (cast(NULL as boolean) AND bool1 IS NOT TRUE AND bool1 IS NOT FALSE) from cx2;
> +--------+
> |  _c0   |
> +--------+
> | true   |
> | false  |
> | NULL   |
> +--------+
> set hive.cbo.enable=false;
> select bool1 IS TRUE OR (cast(NULL as boolean) AND bool1 IS NOT TRUE AND bool1 IS NOT FALSE) from cx2;
> +-------+
> |  _c0  |
> +-------+
> | true  |
> | NULL  |
> | NULL  |
> +-------+
> {code}
> from explain it seems the expression was simplified to: {{(_col0 is true or null)}}



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