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new a475f844d8 [Json] Add benchmarks for list json reader (#9507)
a475f844d8 is described below
commit a475f844d8473eb1d69baebf4337e1c1e1de235c
Author: Liam Bao <[email protected]>
AuthorDate: Wed Mar 11 13:50:02 2026 -0400
[Json] Add benchmarks for list json reader (#9507)
# Which issue does this PR close?
<!--
We generally require a GitHub issue to be filed for all bug fixes and
enhancements and this helps us generate change logs for our releases.
You can link an issue to this PR using the GitHub syntax.
-->
- Relates to #9497.
# Rationale for this change
<!--
Why are you proposing this change? If this is already explained clearly
in the issue then this section is not needed.
Explaining clearly why changes are proposed helps reviewers understand
your changes and offer better suggestions for fixes.
-->
Add benchmark for `ListArray` in `json_reader` to support the
performance evaluation of #9497
# What changes are included in this PR?
<!--
There is no need to duplicate the description in the issue here but it
is sometimes worth providing a summary of the individual changes in this
PR.
-->
- Benchmarks for decoding and serialize json list to `ListArray`.
- Benchmarks for `ListArray` and `FixedSizeListArray` json writer
# Are these changes tested?
<!--
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1. Prevent the code from being accidentally broken by subsequent changes
2. Serve as another way to document the expected behavior of the code
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Benchmarks only
# Are there any user-facing changes?
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If there are user-facing changes then we may require documentation to be
updated before approving the PR.
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No
---
arrow-json/Cargo.toml | 6 +-
.../benches/{json-reader.rs => json_reader.rs} | 87 +++++++++++++-
arrow-json/benches/json_writer.rs | 129 +++++++++++++++++++++
3 files changed, 220 insertions(+), 2 deletions(-)
diff --git a/arrow-json/Cargo.toml b/arrow-json/Cargo.toml
index 5fcde480eb..be1f8d0ccd 100644
--- a/arrow-json/Cargo.toml
+++ b/arrow-json/Cargo.toml
@@ -67,5 +67,9 @@ name = "serde"
harness = false
[[bench]]
-name = "json-reader"
+name = "json_reader"
+harness = false
+
+[[bench]]
+name = "json_writer"
harness = false
diff --git a/arrow-json/benches/json-reader.rs
b/arrow-json/benches/json_reader.rs
similarity index 73%
rename from arrow-json/benches/json-reader.rs
rename to arrow-json/benches/json_reader.rs
index 504839f8ff..f87ba695eb 100644
--- a/arrow-json/benches/json-reader.rs
+++ b/arrow-json/benches/json_reader.rs
@@ -32,6 +32,8 @@ const BATCH_SIZE: usize = 1 << 13; // 8K rows per batch
const WIDE_FIELDS: usize = 64;
const BINARY_BYTES: usize = 64;
const WIDE_PROJECTION_TOTAL_FIELDS: usize = 100; // 100 fields total, select
only 3
+const LIST_SHORT_ELEMENTS: usize = 5;
+const LIST_LONG_ELEMENTS: usize = 100;
fn decode_and_flush(decoder: &mut Decoder, data: &[u8]) {
let mut offset = 0;
@@ -240,11 +242,94 @@ fn bench_wide_projection(c: &mut Criterion) {
);
}
+fn build_list_json(rows: usize, elements: usize) -> Vec<u8> {
+ // Builds newline-delimited JSON objects with a single list field.
+ // Example (rows=2, elements=3):
+ // {"list":[0,1,2]}
+ // {"list":[1,2,3]}
+ let mut out = String::with_capacity(rows * (elements * 6 + 16));
+ for row in 0..rows {
+ out.push_str("{\"list\":[");
+ for i in 0..elements {
+ if i > 0 {
+ out.push(',');
+ }
+ write!(&mut out, "{}", (row + i) as i64).unwrap();
+ }
+ out.push_str("]}\n");
+ }
+ out.into_bytes()
+}
+
+fn build_list_values(rows: usize, elements: usize) -> Vec<Value> {
+ // Mirrors build_list_json but returns structured serde_json::Value
objects.
+ let mut out = Vec::with_capacity(rows);
+ for row in 0..rows {
+ let arr: Vec<Value> = (0..elements)
+ .map(|i| Value::Number(Number::from((row + i) as i64)))
+ .collect();
+ let mut map = Map::with_capacity(1);
+ map.insert("list".to_string(), Value::Array(arr));
+ out.push(Value::Object(map));
+ }
+ out
+}
+
+fn build_list_schema() -> Arc<Schema> {
+ Arc::new(Schema::new(vec![Field::new(
+ "list",
+ DataType::List(Arc::new(Field::new_list_field(DataType::Int64,
false))),
+ false,
+ )]))
+}
+
+fn bench_decode_list(c: &mut Criterion) {
+ let schema = build_list_schema();
+
+ // Short lists: tests list handling overhead (few elements per row)
+ let short_data = build_list_json(ROWS, LIST_SHORT_ELEMENTS);
+ bench_decode_schema(c, "decode_list_short_i64_json", &short_data,
schema.clone());
+
+ // Long lists: tests child element decode throughput (many elements per
row)
+ let long_data = build_list_json(ROWS, LIST_LONG_ELEMENTS);
+ bench_decode_schema(c, "decode_list_long_i64_json", &long_data, schema);
+}
+
+fn bench_serialize_list(c: &mut Criterion) {
+ let schema = build_list_schema();
+
+ let short_values = build_list_values(ROWS, LIST_SHORT_ELEMENTS);
+ c.bench_function("decode_list_short_i64_serialize", |b| {
+ b.iter(|| {
+ let mut decoder = ReaderBuilder::new(schema.clone())
+ .with_batch_size(BATCH_SIZE)
+ .build_decoder()
+ .unwrap();
+ decoder.serialize(&short_values).unwrap();
+ while let Some(_batch) = decoder.flush().unwrap() {}
+ })
+ });
+
+ let long_values = build_list_values(ROWS, LIST_LONG_ELEMENTS);
+ c.bench_function("decode_list_long_i64_serialize", |b| {
+ b.iter(|| {
+ let mut decoder = ReaderBuilder::new(schema.clone())
+ .with_batch_size(BATCH_SIZE)
+ .build_decoder()
+ .unwrap();
+ decoder.serialize(&long_values).unwrap();
+ while let Some(_batch) = decoder.flush().unwrap() {}
+ })
+ });
+}
+
criterion_group!(
benches,
bench_decode_wide_object,
bench_serialize_wide_object,
bench_binary_hex,
- bench_wide_projection
+ bench_wide_projection,
+ bench_decode_list,
+ bench_serialize_list
);
criterion_main!(benches);
diff --git a/arrow-json/benches/json_writer.rs
b/arrow-json/benches/json_writer.rs
new file mode 100644
index 0000000000..b37ea542ef
--- /dev/null
+++ b/arrow-json/benches/json_writer.rs
@@ -0,0 +1,129 @@
+// 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::builder::{FixedSizeListBuilder, Int64Builder, ListBuilder};
+use arrow_array::{Array, RecordBatch};
+use arrow_json::LineDelimitedWriter;
+use arrow_schema::{Field, Schema};
+use criterion::{Criterion, Throughput, criterion_group, criterion_main};
+use std::sync::Arc;
+
+const ROWS: usize = 1 << 17; // 128K rows
+const LIST_SHORT_ELEMENTS: usize = 5;
+const LIST_LONG_ELEMENTS: usize = 100;
+
+fn build_list_batch(rows: usize, elements: usize) -> RecordBatch {
+ let mut list_builder = ListBuilder::new(Int64Builder::new());
+ for row in 0..rows {
+ for i in 0..elements {
+ list_builder.values().append_value((row + i) as i64);
+ }
+ list_builder.append(true);
+ }
+ let list_array = list_builder.finish();
+
+ let schema = Arc::new(Schema::new(vec![Field::new(
+ "list",
+ list_array.data_type().clone(),
+ false,
+ )]));
+
+ RecordBatch::try_new(schema, vec![Arc::new(list_array)]).unwrap()
+}
+
+fn bench_write_list(c: &mut Criterion) {
+ let short_batch = build_list_batch(ROWS, LIST_SHORT_ELEMENTS);
+ let long_batch = build_list_batch(ROWS, LIST_LONG_ELEMENTS);
+
+ let mut group = c.benchmark_group("write_list_i64");
+ // Short lists: tests per-list overhead (few elements per row)
+ group.throughput(Throughput::Elements(ROWS as u64));
+ group.bench_function("short", |b| {
+ let mut buf = Vec::with_capacity(ROWS * LIST_SHORT_ELEMENTS * 8);
+ b.iter(|| {
+ buf.clear();
+ let mut writer = LineDelimitedWriter::new(&mut buf);
+ writer.write(&short_batch).unwrap();
+ writer.finish().unwrap();
+ })
+ });
+
+ // Long lists: tests child element encode throughput (many elements per
row)
+ group.bench_function("long", |b| {
+ let mut buf = Vec::with_capacity(ROWS * LIST_LONG_ELEMENTS * 8);
+ b.iter(|| {
+ buf.clear();
+ let mut writer = LineDelimitedWriter::new(&mut buf);
+ writer.write(&long_batch).unwrap();
+ writer.finish().unwrap();
+ })
+ });
+
+ group.finish();
+}
+
+fn build_fixed_size_list_batch(rows: usize, elements: usize) -> RecordBatch {
+ let mut builder = FixedSizeListBuilder::new(Int64Builder::new(), elements
as i32);
+ for row in 0..rows {
+ for i in 0..elements {
+ builder.values().append_value((row + i) as i64);
+ }
+ builder.append(true);
+ }
+ let list_array = builder.finish();
+
+ let schema = Arc::new(Schema::new(vec![Field::new(
+ "fixed_size_list",
+ list_array.data_type().clone(),
+ false,
+ )]));
+
+ RecordBatch::try_new(schema, vec![Arc::new(list_array)]).unwrap()
+}
+
+fn bench_write_fixed_size_list(c: &mut Criterion) {
+ let short_batch = build_fixed_size_list_batch(ROWS, LIST_SHORT_ELEMENTS);
+ let long_batch = build_fixed_size_list_batch(ROWS, LIST_LONG_ELEMENTS);
+
+ let mut group = c.benchmark_group("write_fixed_size_list_i64");
+ group.throughput(Throughput::Elements(ROWS as u64));
+
+ group.bench_function("short", |b| {
+ let mut buf = Vec::with_capacity(ROWS * LIST_SHORT_ELEMENTS * 8);
+ b.iter(|| {
+ buf.clear();
+ let mut writer = LineDelimitedWriter::new(&mut buf);
+ writer.write(&short_batch).unwrap();
+ writer.finish().unwrap();
+ })
+ });
+
+ group.bench_function("long", |b| {
+ let mut buf = Vec::with_capacity(ROWS * LIST_LONG_ELEMENTS * 8);
+ b.iter(|| {
+ buf.clear();
+ let mut writer = LineDelimitedWriter::new(&mut buf);
+ writer.write(&long_batch).unwrap();
+ writer.finish().unwrap();
+ })
+ });
+
+ group.finish();
+}
+
+criterion_group!(benches, bench_write_list, bench_write_fixed_size_list);
+criterion_main!(benches);
