findepi commented on PR #14668:
URL: https://github.com/apache/datafusion/pull/14668#issuecomment-2672254750
I bencharked
```rust
#[excalibur_function]
fn character_length(s: &str) -> i32 {
s.chars().count() as i32
}
```
comparing it with the `character_length` implementation we ship today
https://github.com/apache/datafusion/blob/f31ca5b927c040ce03f6a3c8c8dc3d7f4ef5be34/datafusion/functions/src/unicode/character_length.rs#L48-L175
I don't have expectations that generic implementation will be faster than
50x[^1] longer, hand-written and optimized code.
Rather, I wanted to check what can be a performance difference between
simple 4-liner implementation and one that has dedicated code paths for
ascii/unicode, nulls/non-nulls and Utf8/Utf8View combinations. I.e. anything
but not "simple".
<details>
<summary>The standard implementation is a bit faster at short
strings</summary>
<img width="1226" alt="image"
src="https://github.com/user-attachments/assets/a23739bb-2e24-4945-ab3e-d0d583b7c9d0";
/>
</details>
<details>
<summary>The generic implementation is a bit faster at long ASCII
strings</summary>
<img width="1188" alt="image"
src="https://github.com/user-attachments/assets/9d19c61e-d00d-4c59-9dac-989da6d2c8b3";
/>
</details>
[^1]: including unit tests code, which is natural necessity in a non-trivial
implementation, but excluding docs
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