planner: allow TableDual to match the required property if the row count is 0 (#16927) #17016
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cherry-pick #16927 to release-4.0
What problem does this PR solve?
Issue Number: close #16841
Problem Summary:
Before this PR, PhysicalTableDual cannot match any required property(and it will return an invalidTask in findBestTask if the property is not empty).
But the case in #16841 use a
MergeJoinhint to enforce to use the merge join. While one child of the LogicalJoin is a LogicalTableDual, which cannot match the property. So the optimizer cannot find a physical plan for that SQL.What is changed and how it works?
What's Changed:
This PR allow TableDual to match the required property if the row count is 0.
How it Works:
Related changes
Check List
Tests
Release note