perf: Optimize repeat function for scalar and array fast#19976
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Jefffrey merged 3 commits intoapache:mainfrom Jan 27, 2026
Merged
perf: Optimize repeat function for scalar and array fast#19976Jefffrey merged 3 commits intoapache:mainfrom
Jefffrey merged 3 commits intoapache:mainfrom
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Jefffrey
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Jan 25, 2026
Jefffrey
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Jan 25, 2026
Jefffrey
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Jan 26, 2026
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Thanks @kumarUjjawal |
de-bgunter
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## 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. --> - Part of apache/datafusion-comet#2986. ## Rationale for this change The `repeat` function currently converts scalar inputs to arrays before processing via `make_scalar_function`. Adding a scalar fast path avoids this overhead and improves performance for constant folding and scalar expression evaluation. <!-- 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. --> ## What changes are included in this PR? 1. Refactored `invoke_with_args` to handle scalar inputs directly without array conversion 2. Added scalar fast path for `Utf8`, `LargeUtf8`, and `Utf8View` scalar inputs 3. Added array fast path that skips per-element null checks when `null_count() == 0` | Type | Before | After | Speedup | |------|--------|-------|---------| | **repeat/scalar_utf8** | 519 ns | 91 ns | **5.7x** | | **repeat/scalar_utf8view** | 437 ns | 91 ns | **4.8x** | <!-- 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. --> ## Are these changes tested? Yes <!-- 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 If tests are not included in your PR, please explain why (for example, are they covered by existing tests)? --> ## Are there any user-facing changes? No <!-- 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. -->
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Which issue does this PR close?
Rationale for this change
The
repeatfunction currently converts scalar inputs to arrays before processing viamake_scalar_function. Adding a scalar fast path avoids this overhead and improves performance for constant folding and scalar expression evaluation.What changes are included in this PR?
invoke_with_argsto handle scalar inputs directly without array conversionUtf8,LargeUtf8, andUtf8Viewscalar inputsnull_count() == 0Are these changes tested?
Yes
Are there any user-facing changes?
No