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perf: Prune matched right rows in nested loop semi and anti joins - #25413
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## main #25413 +/- ##
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+ Coverage 82.71% 82.76% +0.04%
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Files 1147 1147
Lines 447818 448598 +780
Branches 447818 448598 +780
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+ Hits 370412 371267 +855
- Misses 54919 54932 +13
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nlj benchmark (excerpt) |
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Thanks @kosiew for the review! |
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Omega359
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Oct 11, 2026
…ache#25413) ## Which issue does this PR close? <!-- We generally require a GitHub issue to be filed for all bug fixes and enhancements and this helps us generate change logs for our releases. You can link an issue to this PR using the GitHub syntax. For example `Closes apache#123` indicates that this PR will close issue apache#123. --> - Closes #. ## Rationale for this change <!-- Why are you proposing this change? If this is already explained clearly in the issue then this section is not needed. Explaining clearly why changes are proposed helps reviewers understand your changes and offer better suggestions for fixes. Please explain the problem you are trying to solve in terms of the user-visible behavior, rather than the implementation. For example, "The code in `foo.rs` doesn't handle nulls" is a symptom of the implementation. "COUNT(DISTINCT) returns wrong results when the column contains nulls" is the user-visible problem. --> For `RightSemi` and `RightAnti` nested loop joins, each right row only needs one match to determine whether it belongs in the result. Currently, matched right rows continue participating in comparisons with subsequent left rows. Skipping these comparisons can significantly reduce execution time when matches are found early. ## What changes are included in this PR? <!-- There is no need to duplicate the description in the issue here, but it is sometimes worth providing a summary of the individual changes in this PR. --> - Add `RightExistenceProbe` to track matches and right-side candidates. - Compact the right-side filter columns when at least half the candidates have matched and more left rows remain. - Stop probing the current right batch when all its rows have matched. - Preserve matches in original right-row coordinates for output and spill handling. ## What is the testing strategy for this PR? <!-- We typically require tests for all PRs in order to: 1. Prevent the code from being accidentally broken by subsequent changes 2. Serve as another way to document the expected behavior of the code Briefly describe how this PR is tested, and point to the specific tests you added. For example: 'This new feature is covered by the `sqllogictest` cases added in `foo.slt`'. If this PR does not add tests, explain why. For example, if the change is already covered by existing tests, please mention it. You should also check the `codecov` bot reply on this PR to confirm the changed code is exercised. --> - Add unit tests for match tracking and candidate compaction. - Add SQL coverage in `nested_loop_join_existence.slt` for RightSemi/RightAnti joins, including NULLs, repeated matches, and multiple left rows per probe. - Extend `nested_loop_join_spill.slt` to cover RightSemi/RightAnti joins across spilled left chunks. ## Are there any user-facing changes? <!-- If there are user-facing changes then we may require documentation to be updated before approving the PR. If there are any breaking changes to public APIs, please add the `api change` label. --> No. This is an internal performance optimization. ## Benchmark results | Case | Scenario | main | This PR | Time change | |---|---|---:|---:|---:| | Q15 | Right Semi, early matches | 307.659 | 0.365 | -99.88% | | Q16 | Right Anti, early matches | 306.225 | 0.338 | -99.89% | | Q18 | Right Semi, no matches | 7.964 | 7.728 | -2.95% | | Q19 | Right Anti, no matches | 8.100 | 7.770 | -4.07% | | Q20 | Right Semi, staged compaction | 56.082 | 7.182 | -87.19% | | Q21 | Right Anti, staged compaction | 56.057 | 7.115 | -87.31% | | Q22 | Right Semi, repeated 40% matches (4,096 left × 8,192 right) | 12.185 | 12.410 | +1.84% | | Q23 | Right Anti, final-left-row matches with wide Utf8 | 0.305125 | 0.309042 | +1.28% | Co-authored-by: kosiew <kosiew@gmail.com>
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Which issue does this PR close?
Rationale for this change
For
RightSemiandRightAntinested loop joins, each right row only needs one match to determine whether it belongs in the result. Currently, matched right rows continue participating in comparisons with subsequent left rows.Skipping these comparisons can significantly reduce execution time when matches are found early.
What changes are included in this PR?
RightExistenceProbeto track matches and right-side candidates.What is the testing strategy for this PR?
nested_loop_join_existence.sltfor RightSemi/RightAnti joins, including NULLs, repeated matches, and multiple left rows per probe.nested_loop_join_spill.sltto cover RightSemi/RightAnti joins across spilled left chunks.Are there any user-facing changes?
No. This is an internal performance optimization.
Benchmark results