Add benchmark for casting to RunEndEncoded (REE)

Author: vegarsti

arrow-cast/Cargo.toml

@@ -74,3 +74,7 @@ harness = false
 [[bench]]
 name = "parse_decimal"
 harness = false
+
+[[bench]]
+name = "cast_ree"
+harness = false

arrow-cast/benches/cast_ree.rs

@@ -0,0 +1,57 @@
+// 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.
+
+use arrow_array::*;
+use arrow_cast::cast;
+use arrow_schema::{DataType, Field};
+use criterion::*;
+use std::sync::Arc;
+
+fn criterion_benchmark(c: &mut Criterion) {
+    c.bench_function("single run", |b| {
+        let source_array = StringArray::from(vec!["a"; 1000000]);
+        let array_ref = Arc::new(source_array) as ArrayRef;
+        let target_type = DataType::RunEndEncoded(
+            Arc::new(Field::new("run_ends", DataType::Int32, false)),
+            Arc::new(Field::new("values", DataType::Utf8, true)),
+        );
+        b.iter(|| cast(&array_ref, &target_type).unwrap());
+    });
+
+    c.bench_function("many short runs", |b| {
+        let source_array: Int32Array = (0..1000000).map(|i| i / 10).collect();
+        let array_ref = Arc::new(source_array) as ArrayRef;
+        let target_type = DataType::RunEndEncoded(
+            Arc::new(Field::new("run_ends", DataType::Int32, false)),
+            Arc::new(Field::new("values", DataType::Int32, true)),
+        );
+        b.iter(|| cast(&array_ref, &target_type).unwrap());
+    });
+
+    c.bench_function("no runs", |b| {
+        let source_array: Int32Array = (0..1000000).collect();
+        let array_ref = Arc::new(source_array) as ArrayRef;
+        let target_type = DataType::RunEndEncoded(
+            Arc::new(Field::new("run_ends", DataType::Int32, false)),
+            Arc::new(Field::new("values", DataType::Int32, true)),
+        );
+        b.iter(|| cast(&array_ref, &target_type).unwrap());
+    });
+}
+
+criterion_group!(benches, criterion_benchmark);
+criterion_main!(benches);