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Merged
Jefffrey merged 1 commit into from
Jan 15, 2026
+111 −49
Merged

perf: Optimize initcap scalar performance #19776

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125 changes: 77 additions & 48 deletions datafusion/functions/benches/initcap.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -22,12 +22,14 @@ use arrow::datatypes::{DataType, Field};
use arrow::util::bench_util::{
create_string_array_with_len, create_string_view_array_with_len,
};
use criterion::{Criterion, criterion_group, criterion_main};
use criterion::{Criterion, SamplingMode, criterion_group, criterion_main};
use datafusion_common::ScalarValue;
use datafusion_common::config::ConfigOptions;
use datafusion_expr::{ColumnarValue, ScalarFunctionArgs};
use datafusion_functions::unicode;
use std::hint::black_box;
use std::sync::Arc;
use std::time::Duration;

fn create_args<O: OffsetSizeTrait>(
size: usize,
Expand All @@ -49,60 +51,87 @@ fn create_args<O: OffsetSizeTrait>(

fn criterion_benchmark(c: &mut Criterion) {
let initcap = unicode::initcap();
for size in [1024, 4096] {
let args = create_args::<i32>(size, 8, true);
let arg_fields = args
.iter()
.enumerate()
.map(|(idx, arg)| {
Field::new(format!("arg_{idx}"), arg.data_type(), true).into()
})
.collect::<Vec<_>>();
let config_options = Arc::new(ConfigOptions::default());

c.bench_function(
format!("initcap string view shorter than 12 [size={size}]").as_str(),
|b| {
b.iter(|| {
black_box(initcap.invoke_with_args(ScalarFunctionArgs {
args: args.clone(),
arg_fields: arg_fields.clone(),
number_rows: size,
return_field: Field::new("f", DataType::Utf8View, true).into(),
config_options: Arc::clone(&config_options),
}))
})
},
);

let args = create_args::<i32>(size, 16, true);
c.bench_function(
format!("initcap string view longer than 12 [size={size}]").as_str(),
|b| {
b.iter(|| {
black_box(initcap.invoke_with_args(ScalarFunctionArgs {
args: args.clone(),
arg_fields: arg_fields.clone(),
number_rows: size,
return_field: Field::new("f", DataType::Utf8View, true).into(),
config_options: Arc::clone(&config_options),
}))
})
},
);

let args = create_args::<i32>(size, 16, false);
c.bench_function(format!("initcap string [size={size}]").as_str(), |b| {
let config_options = Arc::new(ConfigOptions::default());

// Grouped benchmarks for array sizes - to compare with scalar performance
for size in [1024, 4096, 8192] {
let mut group = c.benchmark_group(format!("initcap size={size}"));
group.sampling_mode(SamplingMode::Flat);
group.sample_size(10);
group.measurement_time(Duration::from_secs(10));

// Array benchmark - Utf8
let array_args = create_args::<i32>(size, 16, false);
let array_arg_fields = vec![Field::new("arg_0", DataType::Utf8, true).into()];
let batch_len = size;

group.bench_function("array_utf8", |b| {
b.iter(|| {
black_box(initcap.invoke_with_args(ScalarFunctionArgs {
args: args.clone(),
arg_fields: arg_fields.clone(),
number_rows: size,
args: array_args.clone(),
arg_fields: array_arg_fields.clone(),
number_rows: batch_len,
return_field: Field::new("f", DataType::Utf8, true).into(),
config_options: Arc::clone(&config_options),
}))
})
});

// Array benchmark - Utf8View
let array_view_args = create_args::<i32>(size, 16, true);
let array_view_arg_fields =
vec![Field::new("arg_0", DataType::Utf8View, true).into()];

group.bench_function("array_utf8view", |b| {
b.iter(|| {
black_box(initcap.invoke_with_args(ScalarFunctionArgs {
args: array_view_args.clone(),
arg_fields: array_view_arg_fields.clone(),
number_rows: batch_len,
return_field: Field::new("f", DataType::Utf8View, true).into(),
config_options: Arc::clone(&config_options),
}))
})
});

// Scalar benchmark - Utf8 (the optimization we added)
let scalar_args = vec![ColumnarValue::Scalar(ScalarValue::Utf8(Some(
"hello world test string".to_string(),
)))];
let scalar_arg_fields = vec![Field::new("arg_0", DataType::Utf8, false).into()];

group.bench_function("scalar_utf8", |b| {
b.iter(|| {
black_box(initcap.invoke_with_args(ScalarFunctionArgs {
args: scalar_args.clone(),
arg_fields: scalar_arg_fields.clone(),
number_rows: 1,
return_field: Field::new("f", DataType::Utf8, false).into(),
config_options: Arc::clone(&config_options),
}))
})
});

// Scalar benchmark - Utf8View
let scalar_view_args = vec![ColumnarValue::Scalar(ScalarValue::Utf8View(Some(
"hello world test string".to_string(),
)))];
let scalar_view_arg_fields =
vec![Field::new("arg_0", DataType::Utf8View, false).into()];

group.bench_function("scalar_utf8view", |b| {
b.iter(|| {
black_box(initcap.invoke_with_args(ScalarFunctionArgs {
args: scalar_view_args.clone(),
arg_fields: scalar_view_arg_fields.clone(),
number_rows: 1,
return_field: Field::new("f", DataType::Utf8View, false).into(),
config_options: Arc::clone(&config_options),
}))
})
});

group.finish();
}
}

Expand Down
35 changes: 34 additions & 1 deletion datafusion/functions/src/unicode/initcap.rs
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,7 @@ use arrow::datatypes::DataType;
use crate::utils::{make_scalar_function, utf8_to_str_type};
use datafusion_common::cast::{as_generic_string_array, as_string_view_array};
use datafusion_common::types::logical_string;
use datafusion_common::{Result, exec_err};
use datafusion_common::{Result, ScalarValue, exec_err};
use datafusion_expr::{
Coercion, ColumnarValue, Documentation, ScalarUDFImpl, Signature, TypeSignatureClass,
Volatility,
Expand Down Expand Up @@ -99,6 +99,39 @@ impl ScalarUDFImpl for InitcapFunc {
&self,
args: datafusion_expr::ScalarFunctionArgs,
) -> Result<ColumnarValue> {
let arg = &args.args[0];

// Scalar fast path - handle directly without array conversion
if let ColumnarValue::Scalar(scalar) = arg {
return match scalar {
ScalarValue::Utf8(None)
| ScalarValue::LargeUtf8(None)
| ScalarValue::Utf8View(None) => Ok(arg.clone()),
ScalarValue::Utf8(Some(s)) => {
let mut result = String::new();
initcap_string(s, &mut result);
Ok(ColumnarValue::Scalar(ScalarValue::Utf8(Some(result))))
}
ScalarValue::LargeUtf8(Some(s)) => {
let mut result = String::new();
initcap_string(s, &mut result);
Ok(ColumnarValue::Scalar(ScalarValue::LargeUtf8(Some(result))))
}
ScalarValue::Utf8View(Some(s)) => {
let mut result = String::new();
initcap_string(s, &mut result);
Ok(ColumnarValue::Scalar(ScalarValue::Utf8View(Some(result))))
}
other => {
exec_err!(
"Unsupported data type {:?} for function `initcap`",
other.data_type()
)
}
};
}

// Array path
let args = &args.args;
match args[0].data_type() {
DataType::Utf8 => make_scalar_function(initcap::<i32>, vec![])(args),
Expand Down