datafusion Optimize char expression

Which issue does this PR close?

#16009

Rationale for this change

What changes are included in this PR?

Are these changes tested?

Are there any user-facing changes?

May 17 '25 21:05 ajita-asthana

Which issue does this PR close?

Closes #16009

Rationale for this change

What changes are included in this PR?

Are these changes tested?

Are there any user-facing changes?

May 17 '25 21:05 ajita-asthana

Hi @ajita-asthana, are you still working on this issue?

consider implementing a benchmark like this first(in a separate PR) to measure the performance of current chr function against the one you have implemented.

You should also mark this as a draft PR till then.

May 23 '25 21:05 logan-keede

Hey @logan-keede, I am. Will do the benchmarking.

May 24 '25 01:05 ajita-asthana

Hey @logan-keede I am running into import errors unlinked crate. I tried extern crate module_name and it did not work. The benchmarks are failing because the rust file is not compiled. Could you please let me how I can resolve the linking errors.

Jul 07 '25 22:07 ajita-asthana

Dependencies in rust needs to be mentioned in Cargo.toml of the crate. Have you done that?

Jul 08 '25 05:07 logan-keede

@logan-keede could you please review this when you have time.

Jul 17 '25 11:07 ajita-asthana

I do see a small performance improvement with these changes:

char                    time:   [9.9009 µs 9.9636 µs 10.036 µs]
                        change: [-3.3878% -2.8089% -2.2840%] (p = 0.00 < 0.05)
                        Performance has improved.

Aug 07 '25 14:08 andygrove