benches: add lower benches for stringview

datafusion/functions/benches/lower.rs

@@ -17,8 +17,10 @@
 
 extern crate criterion;
 
-use arrow::array::{ArrayRef, StringArray};
-use arrow::util::bench_util::create_string_array_with_len;
+use arrow::array::{ArrayRef, StringArray, StringViewBuilder};
+use arrow::util::bench_util::{
+    create_string_array_with_len, create_string_view_array_with_len,
+};
 use criterion::{black_box, criterion_group, criterion_main, Criterion};
 use datafusion_expr::ColumnarValue;
 use datafusion_functions::string;
@@ -65,6 +67,58 @@ fn create_args3(size: usize) -> Vec<ColumnarValue> {
     vec![ColumnarValue::Array(array)]
 }
 
+/// Create an array of args containing StringViews, where all the values in the
+/// StringViews are ASCII.
+/// * `size` - the length of the StringViews, and
+/// * `str_len` - the length of the strings within the array.
+/// * `null_density` - the density of null values in the array.
+/// * `mixed` - whether the array is mixed between inlined and referenced strings.
+fn create_args4(
+    size: usize,
+    str_len: usize,
+    null_density: f32,
+    mixed: bool,
+) -> Vec<ColumnarValue> {
+    let array = Arc::new(create_string_view_array_with_len(
+        size,
+        null_density,
+        str_len,
+        mixed,
+    ));
+
+    vec![ColumnarValue::Array(array)]
+}
+
+/// Create an array of args containing a StringViewArray, where some of the values in the
+/// array are non-ASCII.
+/// * `size` - the length of the StringArray, and
+/// * `non_ascii_density` - the density of non-ASCII values in the array.
+/// * `null_density` - the density of null values in the array.
+fn create_args5(
+    size: usize,
+    non_ascii_density: f32,
+    null_density: f32,
+) -> Vec<ColumnarValue> {
+    let mut string_view_builder = StringViewBuilder::with_capacity(size);
+    for _ in 0..size {
+        // sample null_density to determine if the value should be null
+        if rand::random::<f32>() < null_density {
+            string_view_builder.append_null();
+            continue;
+        }
+
+        // sample non_ascii_density to determine if the value should be non-ASCII
+        if rand::random::<f32>() < non_ascii_density {
+            string_view_builder.append_value("农历新年农历新年农历新年农历新年农历新年");
+        } else {
+            string_view_builder.append_value("DATAFUSIONDATAFUSIONDATAFUSION");
+        }
+    }
+
+    let array = Arc::new(string_view_builder.finish()) as ArrayRef;
+    vec![ColumnarValue::Array(array)]
+}
+
 fn criterion_benchmark(c: &mut Criterion) {
     let lower = string::lower();
     for size in [1024, 4096, 8192] {
@@ -85,6 +139,40 @@ fn criterion_benchmark(c: &mut Criterion) {
             |b| b.iter(|| black_box(lower.invoke(&args))),
         );
     }
+
+    let sizes = [4096, 8192];
+    let str_lens = [10, 64, 128];
+    let mixes = [true, false];
+    let null_densities = [0.0f32, 0.1f32];
+
+    for null_density in &null_densities {
+        for &mixed in &mixes {
+            for &str_len in &str_lens {
+                for &size in &sizes {
+                    let args = create_args4(size, str_len, *null_density, mixed);
+                    c.bench_function(
+            &format!("lower_all_values_are_ascii_string_views: size: {}, str_len: {}, null_density: {}, mixed: {}",
+                     size, str_len, null_density, mixed),
+            |b| b.iter(|| black_box(lower.invoke(&args))),
+        );
+
+                    let args = create_args4(size, str_len, *null_density, mixed);
+                    c.bench_function(
+            &format!("lower_all_values_are_ascii_string_views: size: {}, str_len: {}, null_density: {}, mixed: {}",
+                     size, str_len, null_density, mixed),
+            |b| b.iter(|| black_box(lower.invoke(&args))),
+        );
+
+                    let args = create_args5(size, 0.1, *null_density);
+                    c.bench_function(
+            &format!("lower_some_values_are_nonascii_string_views: size: {}, str_len: {}, non_ascii_density: {}, null_density: {}, mixed: {}",
+                     size, str_len, 0.1, null_density, mixed),
+            |b| b.iter(|| black_box(lower.invoke(&args))),
+        );
+                }
+            }
+        }
+    }
 }
 
 criterion_group!(benches, criterion_benchmark);