[fix](fe) Fix redundant aggregation in agg-union query plan#62231
Merged
924060929 merged 3 commits intoapache:masterfrom Apr 10, 2026
Merged
[fix](fe) Fix redundant aggregation in agg-union query plan#62231924060929 merged 3 commits intoapache:masterfrom
924060929 merged 3 commits intoapache:masterfrom
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Thank you for your contribution to Apache Doris. Please clearly describe your PR:
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### What problem does this PR solve?
Issue Number: close #N/A
Problem Summary: When multiple grouped queries are combined via UNION ALL on randomly distributed tables without PhysicalDistribute operators, Doris was generating redundant local aggregation and global aggregation layers without a distribute operator between them.
The issue was in the `banAggUnionAll` method in ChildrenPropertiesRegulator, which was too aggressively forbidding one-phase aggregation for all agg-union patterns, regardless of whether the union inputs had PhysicalDistribute operators.
### Release note
Improved query optimization: Eliminated redundant aggregation layers in UNION ALL queries with GROUP BY on randomly distributed tables.
### Check List (For Author)
- Test: FE UT and Regression test added
- FE UT: Added AggregateUnionPlanTest to verify correct behavior
- Regression test: Added agg_union_group_by test case to verify execution
- Behavior changed: Yes - query plans are now more optimal with fewer redundant aggregation layers
- Does this need documentation: No
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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run buildall |
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FE UT Coverage ReportIncrement line coverage |
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run feut |
924060929
approved these changes
Apr 10, 2026
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PR approved by at least one committer and no changes requested. |
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PR approved by anyone and no changes requested. |
englefly
approved these changes
Apr 10, 2026
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Problem
When multiple grouped queries are combined via UNION ALL on randomly distributed tables without PhysicalDistribute operators, Doris was generating redundant local aggregation and global aggregation layers without a distribute operator between them.
The issue was in the
banAggUnionAllmethod in ChildrenPropertiesRegulator, which was too aggressively forbidding one-phase aggregation for all agg-union patterns, regardless of whether the union inputs had PhysicalDistribute operators.Solution
Modified the
banAggUnionAllmethod to only forbid one-phase aggregation when the union inputs actually have PhysicalDistribute operators:Test
Added regression test
agg_union_group_by.groovyto verify correct behaviorImpact
Improved query optimization: Eliminated redundant aggregation layers in UNION ALL queries with GROUP BY on randomly distributed tables.