[jira] [Commented] (CALCITE-4432) When the RelNode's input is the same subset as the node belonged to, not choose this node as best.

[Ruben Q L (Jira)]

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https://issues.apache.org/jira/browse/CALCITE-4432?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17254136#comment-17254136
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Ruben Q L commented on CALCITE-4432:
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UPDATE: finally I discovered the root cause of my CyclicMetadataException: it 
was also a metadata cost computation problem. At some point during Volcano 
optimization, an operator had a lower cost than its input's cost. The reason 
for this anomaly was a bug in the RelMdColumnUniqueness computation of a 
certain IndexScan operator in my downstream project.

> When the RelNode's input is the same subset as the node belonged to, not 
> choose this node as best.
> --------------------------------------------------------------------------------------------------
>
>                 Key: CALCITE-4432
>                 URL: https://issues.apache.org/jira/browse/CALCITE-4432
>             Project: Calcite
>          Issue Type: Bug
>          Components: core
>            Reporter: Ziwei Liu
>            Assignee: Ziwei Liu
>            Priority: Major
>
> If a subset have a cyclic node, the node's input is this subset itself. If 
> the beset 



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