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Closes apache#9429 I'm doing some performance optimization, and noticed that we have a loop adding one value to the null mask at a time. Instead, I'd suggest adding `append_non_nulls` to do this at once. ``` append_non_nulls(n) vs append(true) in a loop (with bitmap allocated) ┌───────────┬───────────────────┬─────────────────────┬─────────┐ │ n │ append(true) loop │ append_non_nulls(n) │ speedup │ ├───────────┼───────────────────┼─────────────────────┼─────────┤ │ 100 │ 251 ns │ 73 ns │ ~3x │ ├───────────┼───────────────────┼─────────────────────┼─────────┤ │ 1,000 │ 2.0 µs │ 94 ns │ ~21x │ ├───────────┼───────────────────┼─────────────────────┼─────────┤ │ 10,000 │ 19.3 µs │ 119 ns │ ~162x │ ├───────────┼───────────────────┼─────────────────────┼─────────┤ │ 100,000 │ 191 µs │ 348 ns │ ~549x │ ├───────────┼───────────────────┼─────────────────────┼─────────┤ │ 1,000,000 │ 1.90 ms │ 3.5 µs │ ~543x │ └───────────┴───────────────────┴─────────────────────┴─────────┘ ```
scovich
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Feb 20, 2026
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Do we have in-repo benchmarks that show the improvements, by chance?
| /// Appends `n` non-null entries into the builder. | ||
| #[inline] | ||
| pub fn append_non_nulls(&mut self, n: usize) { | ||
| self.null_buffer_builder.append_n_non_nulls(n); |
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append_nulls below currently appends an n-element vec of false instead of calling its append_n_nulls. It seems like both these methods should follow the same approach -- whichever way is faster?
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Ah, I somehow missed that PR. We have our answer then!
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I've posted the result of a micro-benchmark created by Claude. Let me know if you want to add the benchmark itself as well. Since it is so specific, I left it out, and creating a new one is fairly trivial. |
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Which issue does this PR close?
append_non_nullstoStructBuilder#9429I'm doing some performance optimization, and noticed that we have a loop adding one value to the null mask at a time. Instead, I'd suggest adding
append_non_nullsto do this at once.Rationale for this change
It adds a new public API in favor of performance improvements.
What changes are included in this PR?
A new public API
Are these changes tested?
Yes, with new unit-tests.
Are there any user-facing changes?
Just a new convient API.