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The following commit(s) were added to refs/heads/main by this push:
new aa79c67359 add low card dictionary benchmarks (#10539)
aa79c67359 is described below
commit aa79c673593c89b808851a250f89854ba7ded6e9
Author: RIchard Baah <[email protected]>
AuthorDate: Wed Aug 5 09:57:11 2026 -0400
add low card dictionary benchmarks (#10539)
# Which issue does this PR close?
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enhancements and this helps us generate change logs for our releases.
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- works towards #10465
- related to #2322
- this is pretty much striped from
https://github.com/apache/arrow-rs/pull/9520
# Rationale for this change
we need a way to measure the changes for future work in #10465
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in the issue then this section is not needed.
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your changes and offer better suggestions for fixes.
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# What changes are included in this PR?
this PR adds 3 benchmarks that cover writting record batches of varying
cardinality's.
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is sometimes worth providing a summary of the individual changes in this
PR.
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# Are these changes tested?
n/a
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# Are there any user-facing changes?
no
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Co-authored-by: rich-T-kid <[email protected]>
Co-authored-by: Jeffrey Vo <[email protected]>
---
parquet/benches/arrow_writer.rs | 43 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 43 insertions(+)
diff --git a/parquet/benches/arrow_writer.rs b/parquet/benches/arrow_writer.rs
index 0e9900ee2f..cad8cf163e 100644
--- a/parquet/benches/arrow_writer.rs
+++ b/parquet/benches/arrow_writer.rs
@@ -18,9 +18,11 @@
#[macro_use]
extern crate criterion;
+use arrow_array::builder::StringDictionaryBuilder;
use criterion::{Bencher, Criterion, Throughput};
use parquet::arrow::ArrowWriter;
use parquet::basic::{Compression, Encoding, ZstdLevel};
+use rand::{Rng, distr::Alphanumeric};
use std::hint::black_box;
use std::io::Empty;
@@ -96,6 +98,38 @@ fn create_string_bench_batch(
true_density,
)?)
}
+// Creates a DictionaryArray with target cardinality
+fn create_low_card_dictionary_bench_batch(size: usize, cardinality: usize) ->
Result<RecordBatch> {
+ let mut rng = rand::rng();
+
+ // Generate `cardinality` unique random strings.
+ let categories: Vec<String> = (0..cardinality)
+ .map(|_| {
+ let len = rng.random_range(10..25);
+
+ (0..len).map(|_| rng.sample(Alphanumeric) as char).collect()
+ })
+ .collect();
+
+ let mut builder = StringDictionaryBuilder::<Int32Type>::new();
+
+ for i in 0..size {
+ builder.append_value(&categories[i % cardinality]);
+ }
+
+ let dict = builder.finish();
+
+ let schema = Schema::new(vec![Field::new(
+ "_1",
+ DataType::Dictionary(Box::new(DataType::Int32),
Box::new(DataType::Utf8)),
+ false,
+ )]);
+
+ Ok(RecordBatch::try_new(
+ Arc::new(schema),
+ vec![Arc::new(dict)],
+ )?)
+}
/// 1 M short, fixed-width 8-byte strings. Exercises the BYTE_ARRAY hot path
/// for the case where individual values are small enough that the byte-budget
@@ -569,6 +603,15 @@ fn create_batches() -> Vec<(&'static str, RecordBatch)> {
let batch = create_string_dictionary_bench_batch(BATCH_SIZE, 0.25,
0.75).unwrap();
batches.push(("string_dictionary", batch));
+ let batch = create_low_card_dictionary_bench_batch(BATCH_SIZE,
20).unwrap();
+ batches.push(("string_dictionary_low_cardinality_20", batch));
+
+ let batch = create_low_card_dictionary_bench_batch(BATCH_SIZE,
100).unwrap();
+ batches.push(("string_dictionary_low_cardinality_100", batch));
+
+ let batch = create_low_card_dictionary_bench_batch(BATCH_SIZE,
400).unwrap();
+ batches.push(("string_dictionary_low_cardinality_400", batch));
+
let batch = create_string_bench_batch_non_null(BATCH_SIZE, 0.25,
0.75).unwrap();
batches.push(("string_non_null", batch));
