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new 56fec71c7b Add left function benchmark (#19600)
56fec71c7b is described below
commit 56fec71c7be925d40d6b62897a179a1599ffc071
Author: Liang-Chi Hsieh <[email protected]>
AuthorDate: Fri Jan 2 23:19:16 2026 +0800
Add left function benchmark (#19600)
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- Closes #.
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---
datafusion/functions/Cargo.toml | 5 ++
datafusion/functions/benches/left.rs | 111 +++++++++++++++++++++++++++++++++++
2 files changed, 116 insertions(+)
diff --git a/datafusion/functions/Cargo.toml b/datafusion/functions/Cargo.toml
index 5ceeee57b0..42bc9f6741 100644
--- a/datafusion/functions/Cargo.toml
+++ b/datafusion/functions/Cargo.toml
@@ -294,3 +294,8 @@ required-features = ["unicode_expressions"]
harness = false
name = "levenshtein"
required-features = ["unicode_expressions"]
+
+[[bench]]
+harness = false
+name = "left"
+required-features = ["unicode_expressions"]
diff --git a/datafusion/functions/benches/left.rs
b/datafusion/functions/benches/left.rs
new file mode 100644
index 0000000000..3ea628fe29
--- /dev/null
+++ b/datafusion/functions/benches/left.rs
@@ -0,0 +1,111 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing,
+// software distributed under the License is distributed on an
+// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+// KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations
+// under the License.
+
+extern crate criterion;
+
+use std::hint::black_box;
+use std::sync::Arc;
+
+use arrow::array::{ArrayRef, Int64Array};
+use arrow::datatypes::{DataType, Field};
+use arrow::util::bench_util::create_string_array_with_len;
+use criterion::{BenchmarkId, Criterion, criterion_group, criterion_main};
+use datafusion_common::config::ConfigOptions;
+use datafusion_expr::{ColumnarValue, ScalarFunctionArgs};
+use datafusion_functions::unicode::left;
+
+fn create_args(size: usize, str_len: usize, use_negative: bool) ->
Vec<ColumnarValue> {
+ let string_array = Arc::new(create_string_array_with_len::<i32>(size, 0.1,
str_len));
+
+ // For negative n, we want to trigger the double-iteration code path
+ let n_values: Vec<i64> = if use_negative {
+ (0..size).map(|i| -((i % 10 + 1) as i64)).collect()
+ } else {
+ (0..size).map(|i| (i % 10 + 1) as i64).collect()
+ };
+ let n_array = Arc::new(Int64Array::from(n_values));
+
+ vec![
+ ColumnarValue::Array(string_array),
+ ColumnarValue::Array(Arc::clone(&n_array) as ArrayRef),
+ ]
+}
+
+fn criterion_benchmark(c: &mut Criterion) {
+ for size in [1024, 4096] {
+ let mut group = c.benchmark_group(format!("left size={size}"));
+
+ // Benchmark with positive n (no optimization needed)
+ let args = create_args(size, 32, false);
+ group.bench_function(BenchmarkId::new("positive n", size), |b| {
+ 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());
+
+ b.iter(|| {
+ black_box(
+ left()
+ .invoke_with_args(ScalarFunctionArgs {
+ args: args.clone(),
+ arg_fields: arg_fields.clone(),
+ number_rows: size,
+ return_field: Field::new("f", DataType::Utf8,
true).into(),
+ config_options: Arc::clone(&config_options),
+ })
+ .expect("left should work"),
+ )
+ })
+ });
+
+ // Benchmark with negative n (triggers optimization)
+ let args = create_args(size, 32, true);
+ group.bench_function(BenchmarkId::new("negative n", size), |b| {
+ 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());
+
+ b.iter(|| {
+ black_box(
+ left()
+ .invoke_with_args(ScalarFunctionArgs {
+ args: args.clone(),
+ arg_fields: arg_fields.clone(),
+ number_rows: size,
+ return_field: Field::new("f", DataType::Utf8,
true).into(),
+ config_options: Arc::clone(&config_options),
+ })
+ .expect("left should work"),
+ )
+ })
+ });
+
+ group.finish();
+ }
+}
+
+criterion_group!(benches, criterion_benchmark);
+criterion_main!(benches);
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