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From "Sean Hsuan-Yi Chu (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (DRILL-4477) Wrong Plan (potentially wrong result) if wrapping a query with SELECT * FROM
Date Mon, 14 Mar 2016 21:29:33 GMT

    [ https://issues.apache.org/jira/browse/DRILL-4477?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15194175#comment-15194175
] 

Sean Hsuan-Yi Chu commented on DRILL-4477:
------------------------------------------

It is reproduced on Calcite's Master.

https://issues.apache.org/jira/browse/CALCITE-1154

> Wrong Plan (potentially wrong result) if wrapping a query with SELECT * FROM
> ----------------------------------------------------------------------------
>
>                 Key: DRILL-4477
>                 URL: https://issues.apache.org/jira/browse/DRILL-4477
>             Project: Apache Drill
>          Issue Type: Bug
>          Components: Query Planning & Optimization
>            Reporter: Sean Hsuan-Yi Chu
>            Assignee: Sean Hsuan-Yi Chu
>            Priority: Blocker
>             Fix For: 1.7.0
>
>         Attachments: t1.json, t2.json
>
>
> For example, a query  
> {code}
> select * from (select s.name, v.name, v.registration from cp.`tpch/region.parquet` s
left outer join cp.`tpch/nation.parquet` v
> on (s.name = v.name) 
> where s.age < 30) t 
> {code}
> gives a plan as below:
> {code}
> +------+------+
> | text | json |
> +------+------+
> | 00-00    Screen
> 00-01      Project(name=[$0], name0=[$1], registration=[$2])
> 00-02        Project(name=[$0], name0=[$0], registration=[$3])
> 00-03          Project(name=[$2], age=[$3], name0=[$0], registration=[$1])
> 00-04            HashJoin(condition=[=($2, $0)], joinType=[right])
> 00-06              Scan(groupscan=[ParquetGroupScan [entries=[ReadEntryWithPath [path=classpath:/tpch/nation.parquet]],
selectionRoot=classpath:/tpch/nation.parquet, numFiles=1, usedMetadataFile=false, columns=[`name`,
`registration`]]])
> 00-05              Project(name0=[$0], age=[$1])
> 00-07                SelectionVectorRemover
> 00-08                  Filter(condition=[<($1, 30)])
> 00-09                    Scan(groupscan=[ParquetGroupScan [entries=[ReadEntryWithPath
[path=classpath:/tpch/region.parquet]], selectionRoot=classpath:/tpch/region.parquet, numFiles=1,
usedMetadataFile=false, columns=[`name`, `age`]]])
> {code}
> In the line 00-02, both name and name0 point at the same incoming column (probably due
to the JOIN CONDITION). 
> However. the fact that these two are the JOIN condition does not make a case that they
must be equal since implicit casting might be invoked to perform the JOIN condition.
> Interestingly, if the SELECT * FROM wrapper is removed, this bug won't be exposed: 
> {code}
> select s.name, v.name, v.registration from cp.`tpch/region.parquet` s left outer join
cp.`tpch/nation.parquet` v on (s.name = v.name) 
> where s.age < 30
> {code}
> gives 
> {code}
> 00-00    Screen
> 00-01      Project(name=[$0], name0=[$1], registration=[$2])
> 00-02        Project(name=[$2], name0=[$0], registration=[$1])
> 00-03          HashJoin(condition=[=($2, $0)], joinType=[right])
> 00-05            Scan(groupscan=[ParquetGroupScan [entries=[ReadEntryWithPath [path=classpath:/tpch/nation.parquet]],
selectionRoot=classpath:/tpch/nation.parquet, numFiles=1, usedMetadataFile=false, columns=[`name`,
`registration`]]])
> 00-04            Project(name0=[$0])
> 00-06              Project(name=[$0])
> 00-07                SelectionVectorRemover
> 00-08                  Filter(condition=[<($1, 30)])
> 00-09                    Scan(groupscan=[ParquetGroupScan [entries=[ReadEntryWithPath
[path=classpath:/tpch/region.parquet]], selectionRoot=classpath:/tpch/region.parquet, numFiles=1,
usedMetadataFile=false, columns=[`name`, `age`]]])
> {code}



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