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https://issues.apache.org/jira/browse/CALCITE-6665?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ZheHu resolved CALCITE-6665.
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Fix Version/s: 1.39.0
Resolution: Fixed
Fixed in
[575fc1a|https://github.com/apache/calcite/commit/575fc1a583b3f5b5febdee40da4c5cb46c9022b1],
thanks for the PR! [~nobigo]
Thank you for the review [~caicancai]
> Add isEmpty metadata to check if a relational expression returns no rows
> ------------------------------------------------------------------------
>
> Key: CALCITE-6665
> URL: https://issues.apache.org/jira/browse/CALCITE-6665
> Project: Calcite
> Issue Type: Improvement
> Reporter: xiong duan
> Assignee: xiong duan
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.39.0
>
>
> In Calcite, there are many times to determine whether a relational expression
> returns 0 rows through maxRowCount.
> But some places use `maxRowCount<=1D` while others use `maxRowCount ==0D`.
> This PR mainly aims to add `@Nullable Boolean
> RelMetadataQuery.isEmpty(RelNode)` to unify this behavior.
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