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https://issues.apache.org/jira/browse/HIVE-17535?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16170749#comment-16170749
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Vineet Garg commented on HIVE-17535:
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Latest patch(3) has known failure {{min_structvalue}} which is a bug exposed by
the patch. Queries such as {code:sql} select max(a), min(a) FROM (select
named_struct("field",1) as a union all select named_struct("field",2) as a
union all select named_struct("field",cast(null as int)) as a) tmp{code} fails
with CBO because CBO ends up loosing {{CAST}} operation resulting in
{{named_struct("field",cast(null as int)}} to just
{{named_struct("field",null}}. This results in different schema structure b/w
union statements which is semantically incorrect. {{
This could be reproduced using simple {code:sql}select
named_struct("field",cast(null as int)) as a{code}. If we dump new ast after
CBO we will notice missing CAST operation.
> Select 1 EXCEPT Select 1 fails with NPE
> ---------------------------------------
>
> Key: HIVE-17535
> URL: https://issues.apache.org/jira/browse/HIVE-17535
> Project: Hive
> Issue Type: Bug
> Components: Query Planning
> Reporter: Vineet Garg
> Assignee: Vineet Garg
> Attachments: HIVE-17535.1.patch, HIVE-17535.2.patch,
> HIVE-17535.3.patch
>
>
> Since Hive CBO isn't able to handle queries with no table e.g. {{select 1}}
> queries with SET operators fail (intersect requires CBO).
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