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perf: Prune matched right rows in nested loop semi and anti joins - #25413

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kosiew merged 3 commits into
apache:mainfrom
lyne7-sc:perf/nlj-right-existence-pruning
Oct 9, 2026
Merged

kosiew merged 3 commits into
apache:mainfrom
lyne7-sc:perf/nlj-right-existence-pruning

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Which issue does this PR close?

  • Closes #.

Rationale for this change

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?

  • 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?

  • 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?

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%

@github-actions github-actions Bot added sqllogictest SQL Logic Tests (.slt) physical-plan Changes to the physical-plan crate labels Sep 17, 2026
@codecov-commenter

codecov-commenter commented Sep 17, 2026 •

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Codecov Report

❌ Patch coverage is 87.86408% with 25 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.76%. Comparing base (827ca29) to head (9d19d30).
⚠️ Report is 3 commits behind head on main.

Files with missing lines Patch % Lines
...fusion/physical-plan/src/joins/nested_loop_join.rs 87.86% 10 Missing and 15 partials ⚠️
Additional details and impacted files
@@            Coverage Diff             @@
##             main   #25413      +/-   ##
==========================================
+ Coverage   82.71%   82.76%   +0.04%     
==========================================
  Files        1147     1147              
  Lines      447818   448598     +780     
  Branches   447818   448598     +780     
==========================================
+ Hits       370412   371267     +855     
- Misses      54919    54932      +13     
+ Partials    22487    22399      -88     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

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@kosiew

kosiew commented Oct 6, 2026

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nlj benchmark (excerpt)

Benchmark nlj.json
--------------------
┏━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━┓
┃ Query     ┃       HEAD ┃ bench-25413 ┃          Change ┃
┡━━━━━━━━━━━╇━━━━━━━━━━━━╇━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━┩
│ QQuery 15 │  110.09 ms │     0.58 ms │ +188.66x faster │
│ QQuery 16 │  110.38 ms │     0.59 ms │ +185.80x faster │
└───────────┴────────────┴─────────────┴─────────────────┘

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@lyne7-sc,

Thanks for working on this. The RightSemi/RightAnti probing changes, candidate compaction, payload preservation, spill handling, tests, and benchmarks look good to me.

@lyne7-sc

lyne7-sc commented Oct 8, 2026

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Thanks @kosiew for the review!

@kosiew

kosiew commented Oct 9, 2026

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🚀
@lyne7-sc
Thank you for your contribution.

@kosiew
kosiew added this pull request to the merge queue Oct 9, 2026
Merged via the queue into apache:main with commit 057f77f Oct 9, 2026
83 checks passed
@lyne7-sc
lyne7-sc deleted the perf/nlj-right-existence-pruning branch October 10, 2026 02:03
Omega359 pushed a commit to Omega359/arrow-datafusion that referenced this pull request Oct 11, 2026
…ache#25413)

## Which issue does this PR close?

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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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3 participants