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Dispatch zip kernels on either value branch - #11138

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db/zip-if-false-dispatch
Nov 3, 2026
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blaginin merged 1 commit into
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db/zip-if-false-dispatch

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@blaginin blaginin commented Nov 3, 2026 •

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Normalize if_false dispatch by filling null mask entries with false before inversion.

Closes #10908.

Normalize if_false dispatch by filling null mask entries with false before inversion. This preserves SQL ELSE semantics while allowing both execute and reduce kernels to handle either branch.

Refs #10908.

Signed-off-by: blaginin <[email protected]>
@blaginin blaginin self-assigned this Nov 3, 2026
@blaginin
blaginin marked this pull request as ready for review November 3, 2026 14:34
@blaginin blaginin added the changelog/chore A trivial change label Nov 3, 2026
@blaginin
blaginin requested a review from connortsui20 November 3, 2026 14:34
@codspeed

codspeed Bot commented Nov 3, 2026

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Merging this PR will improve performance by 18.33%

2 warnings

⚠️ Walltime results may be unreliable

Some benchmarks used the Walltime instrument outside CodSpeed Macro Runners, which can make the results inconsistent.

Learn more about Macro Runners

See affected benchmarks

⚠️ 1 benchmark is dominated by system calls

System calls cannot be simulated consistently and are left out of the measure. The reported value understates the real cost. Switch to the Walltime instrument to measure them.

Learn more about system calls

See affected benchmarks

⚡ 3 improved benchmarks
✅ 1874 untouched benchmarks
⏩ 468 skipped benchmarks1

Performance Changes

Mode Benchmark BASE HEAD Efficiency
⚡ CPU Simulation missing_stats[16] 85.1 µs 67.7 µs +25.64%
⚡ CPU Simulation encode_primitives[f32, (2000, 2)] 205 µs 177.3 µs +15.61%
⚡ CPU Simulation take_filter_primitive_small_uncached_random_mask_random_indices[4096, 10] 25 µs 21.9 µs +14.08%

Tip

Curious why performance improved? Comment @codspeedbot explain why performance improved on this PR, or directly use the CodSpeed MCP with your agent.


Comparing db/zip-if-false-dispatch (e2b59e0) with develop (e0d17f6)

Open in CodSpeed

Footnotes

  1. 468 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

@connortsui20 connortsui20 left a comment

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I wonder if there is a more general way to do this so that it is harder to get this wrong? I mostly relied on an LLM to write this so I didn't even consider matching directly on the parent to get the siblings. Should kernels have a standard way to get siblings? cc @robert3005 @joseph-isaacs

@blaginin
blaginin merged commit 7146a1b into develop Nov 3, 2026
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@blaginin
blaginin deleted the db/zip-if-false-dispatch branch November 3, 2026 16:09
@robert3005

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I think this is very much function dependent if you can do this kind of switch. I think there's some prior art in languages like objective-c how to do it but I am not too familiar

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Maybe just need to add some docs instead?

connortsui20 added a commit that referenced this pull request Nov 3, 2026
## Summary

Follow-up to #11110. Keep the remaining noisy cases out of automatic
CodSpeed runs while preserving them for local benchmarks.

The Python scalar exclusions in #11110 never took effect because the
runner exports simulation as `instrumentation`, while the fixture
checked for `simulation`. Use the plugin's resolved mode so these cases
are actually skipped.

## Changes

- Allow a trailing comma in `#[divan::bench(...)]` when the CPU-feature
macro appends its options. The multiline bitpacked take definition
covers this case in CI builds.
- Share the resolved simulation check between the scalar and filter
fixtures. Also skip the 2 integer one-shot filtered scans that still
report system calls under simulation.
- Keep AVX2 bitpacked take with 80 selections local after batching still
produced a regression alert. Retain the 64-selection case and both
AVX-512 cases in CI.
- Keep AVX-512 nullable integer comparison local because its minimum
changes by more than 10% while its median stays stable.
- Keep the small random power-law boolean filter and the large
correlated power-law boolean filter local under simulation. The former
has repeated unexplained changes, and the latter repeatedly makes system
calls that simulation cannot measure.

<details>
<summary>Evidence from recent PR reports</summary>

Reviewed 40 CodSpeed report comments updated between November 2 at 19:28
UTC and November 3 at 19:28 UTC, including their comparison revisions
and the affected measurement modes.

| Case | Evidence |
| --- | --- |
| Python integer scalar scans |
[#11154](#11154 (comment))
still reports the repeated scan's 10 system calls. [A develop run after
#11110](https://github.com/vortex-data/vortex/actions/runs/41677647530/job/126062463160)
executes both integer scalar cases instead of skipping them. The [runner
exports the legacy `instrumentation`
value](https://github.com/CodSpeedHQ/codspeed/blob/main/crates/runner-shared/src/measurement_mode.rs),
which pytest-codspeed 5.0.3 normalizes to simulation. |
| Python integer filtered scans |
[#11130](#11130 (comment))
reports 30 system calls totaling 14.3 ms in `test_scan_filter[int]`.
[#11138](#11138 (comment))
reports 30 calls totaling 16.3 ms in
`test_scan_filter_to_arrow_array[int]`. |
| AVX2 `threshold[80]` |
[#11004](#11004 (comment))
compares `f7b5b1d864` with `e59b236d7b`: 2.183 to 2.531 µs, reported as
a 13.75% regression. Both use 1000 samples of 16 iterations. The head
median is 2.556 µs, so this is not just a single outlying minimum. The
PR does not change the fastlanes code or benchmark. |
| AVX-512 `lt_i64_nullable` |
[#11168](#11168 (comment))
reports 7.342 to 8.217 µs. Several unrelated CUDA PRs report the
opposite direction, including
[#10872](#10872 (comment)),
at 8.208 to 7.348 µs. Their head medians remain around 8.3 to 8.5 µs. |
| Boolean `filter_powerlaw_by_random[10000]` |
[#11167](#11167 (comment))
reports a 16.2% regression,
[#11168](#11168 (comment))
a 23.56% improvement, and
[#11169](#11169 (comment))
a 13.06% regression. The cause is unknown. |
| Boolean `filter_powerlaw_by_correlated_runs[100000]` |
[#10871](#10871 (comment))
and
[#11165](#11165 (comment))
each report 2 system calls totaling about 44 µs. |

The NEON chunked-take alerts on #11090 are on a PR that changes
execution substantially, so those cases remain enabled. Other dictionary
simulation alerts need more attribution before excluding them.

</details>

CI passes formatting, Python lint and script tests, Rust lint,
default-feature and all-feature Rust builds, all 3 CPU walltime
benchmark jobs, and Python benchmarks (36 passed, 4 intentionally
skipped). The previously failed simulation shard also passes. Some
remaining CI jobs and CodSpeed performance analysis are still pending.

No local checks were run. The pre-commit and pre-push hooks were
bypassed as requested.

---------

Signed-off-by: Connor Tsui <[email protected]>
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ZipExecuteAdaptor dispatches only on the if_true branch

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