bug: Eliminate dead round-robin insertion in enforce distribution #19132
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…equire hash repartitioning branch
gene-bordegaray
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alamb
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Dec 9, 2025
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Looks good to me -- thanks @gene-bordegaray
| child = add_merge_on_top(child); | ||
| } | ||
| Distribution::HashPartitioned(exprs) => { | ||
| // See https://github.com/apache/datafusion/issues/18341#issuecomment-3503238325 for background |
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Should we remove this comment too?
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I think I will update this documentation to be accurate. I think it is still useful for people who want to dive into this part of the codebase
…nd_robin_repartition_condition
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Which issue does this PR close?
Rationale for this change
Eliminates dead code that was not used in the enforce distribution rule.
In the branch where a parent requires hash repartitioning, there was a condition that would "add" a round robin if hash was not necessary (already hashed correctly) and the add round-robin flag was marked as true. This condition would never evaluate to true because anytime a parent requires hash repartitioning, we cannot round-robin because it would break the hash partitioning.
What changes are included in this PR?
A condition is deleted. No tests or plans were changed since this was dead code.
Are these changes tested?
Yes, all tests (unit and sqllogictests) still pass.
There is no new tests to add.
Are there any user-facing changes?
No.