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https://issues.apache.org/jira/browse/CALCITE-3977?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17102477#comment-17102477
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Thomas Rebele commented on CALCITE-3977:
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The original plan is a simplified version of a much larger plan. I removed all
rel and rex nodes that do not contribute to the bug. The query corresponding to
the plan doesn't make much sense. As I understand it, the result would be all
authors cross-product all authors from Munich.
I've also removed the requiredColumns. However it didn't change the result. In
order to make use of a2, one could replace 'Munich' by $0.name, to search for
all authors who have the same name as the city they are living in. I can check
on Monday whether it produces the same bug.
Nevertheless, it seems that there are problems with RelDecorrelator if the
query uses field accesses.
> RelDecorrelator does not resolve correlation variable with field accesses
> -------------------------------------------------------------------------
>
> Key: CALCITE-3977
> URL: https://issues.apache.org/jira/browse/CALCITE-3977
> Project: Calcite
> Issue Type: Bug
> Components: core
> Affects Versions: 1.22.0
> Reporter: Thomas Rebele
> Priority: Major
> Attachments: Calcite3977.java
>
>
> The RelCorrelator seems to have problems with some plans that contain a field
> access (probably a RexFieldAccess, but I haven't looked further into it). In
> this ticket there's a filter on *$cor0.birthPlace.city*.
> Here the complete plan:
> {code:java}
> before decorrelate
> LogicalCorrelate(correlation=[$cor0], joinType=[left], requiredColumns=[{}])
> LogicalTableScan(table=[[bookstore, authors]])
> LogicalFilter(condition=[=('Munich', $cor0.birthPlace.city)])
> LogicalTableScan(table=[[bookstore, authors]])
> after decorrelate
> LogicalJoin(condition=[=($2, $8)], joinType=[left])
> LogicalTableScan(table=[[bookstore, authors]])
> LogicalJoin(condition=[true], joinType=[inner])
> LogicalFilter(condition=[=('Munich', $cor0.birthPlace.city)])
> LogicalTableScan(table=[[bookstore, authors]])
> LogicalAggregate(group=[{0}])
> LogicalProject(birthPlace=[$2])
> LogicalTableScan(table=[[bookstore, authors]])
> {code}
> There seem to be two problems:
> * The LogicalCorrelate has been removed, but the $cor0.birthPlace.city is
> still in the filter condition.
> * The inner join does not seem to be necessary. If it is, could somebody
> explain, why?
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