xiong duan created CALCITE-6665:
-----------------------------------
Summary: 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
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.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
