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commit c92ba2962c0fb09255c08172f05430b7aa150f5d Author: Kumar Ujjawal <[email protected]> AuthorDate: Thu Feb 5 06:53:59 2026 +0530 perf: Optimize scalar fast path & write() encoding for sha2 (#20116) ## 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. For example `Closes #123` indicates that this PR will close issue #123. --> - Closes #20046 . ## Rationale for this change Spark `sha2` currently evaluates scalars via `make_scalar_function(sha2_impl, vec![])`, which expands scalar inputs to size-1 arrays before execution. This adds avoidable overhead for scalar evaluation / constant folding scenarios. In addition, the existing digest-to-hex formatting uses `write!(&mut s, "{b:02x}")` in a loop, which is significantly slower than a LUT-based hex encoder. <!-- 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. --> ## What changes are included in this PR? 1) a match-based scalar fast path for `sha2` to avoid scalar→array expansion, and 2) a faster LUT-based hex encoder to replace `write!` formatting. | Benchmark | Before | After | Speedup | |----------|--------|-------|---------| | `sha2/scalar/size=1` | 1.0408 µs | 339.29 ns | **~3.07x** | | `sha2/array_binary_256/size=1024` | 604.13 µs | 295.09 µs | **~2.05x** | | `sha2/array_binary_256/size=4096` | 2.3508 ms | 1.2095 ms | **~1.94x** | | `sha2/array_binary_256/size=8192` | 4.5192 ms | 2.2826 ms | **~1.98x** | <!-- 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. --> ## Are these changes tested? Yes <!-- We typically require tests for all PRs in order to: 1. Prevent the code from being accidentally broken by subsequent changes 2. Serve as another way to document the expected behavior of the code If tests are not included in your PR, please explain why (for example, are they covered by existing tests)? --> ## Are there any user-facing changes? No <!-- If there are user-facing changes then we may require documentation to be updated before approving the PR. --> <!-- If there are any breaking changes to public APIs, please add the `api change` label. --> --------- Co-authored-by: Jeffrey Vo <[email protected]> Co-authored-by: Martin Grigorov <[email protected]> Co-authored-by: Oleks V <[email protected]> --- datafusion/spark/Cargo.toml | 4 + datafusion/spark/benches/sha2.rs | 107 ++++++++++++++++++++++ datafusion/spark/src/function/hash/sha2.rs | 139 ++++++++++++++++++++++++++--- 3 files changed, 240 insertions(+), 10 deletions(-) diff --git a/datafusion/spark/Cargo.toml b/datafusion/spark/Cargo.toml index 466c17b78..8a5c68a5d 100644 --- a/datafusion/spark/Cargo.toml +++ b/datafusion/spark/Cargo.toml @@ -92,3 +92,7 @@ name = "substring" [[bench]] harness = false name = "unhex" + +[[bench]] +harness = false +name = "sha2" diff --git a/datafusion/spark/benches/sha2.rs b/datafusion/spark/benches/sha2.rs new file mode 100644 index 000000000..8ab602d31 --- /dev/null +++ b/datafusion/spark/benches/sha2.rs @@ -0,0 +1,107 @@ +// 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 arrow::array::*; +use arrow::datatypes::*; +use criterion::{Criterion, criterion_group, criterion_main}; +use datafusion_common::ScalarValue; +use datafusion_common::config::ConfigOptions; +use datafusion_expr::{ColumnarValue, ScalarFunctionArgs, ScalarUDFImpl}; +use datafusion_spark::function::hash::sha2::SparkSha2; +use rand::rngs::StdRng; +use rand::{Rng, SeedableRng}; +use std::hint::black_box; +use std::sync::Arc; + +fn seedable_rng() -> StdRng { + StdRng::seed_from_u64(42) +} + +fn generate_binary_data(size: usize, null_density: f32) -> BinaryArray { + let mut rng = seedable_rng(); + let mut builder = BinaryBuilder::new(); + for _ in 0..size { + if rng.random::<f32>() < null_density { + builder.append_null(); + } else { + let len = rng.random_range::<usize, _>(1..=100); + let bytes: Vec<u8> = (0..len).map(|_| rng.random()).collect(); + builder.append_value(&bytes); + } + } + builder.finish() +} + +fn run_benchmark(c: &mut Criterion, name: &str, size: usize, args: &[ColumnarValue]) { + let sha2_func = SparkSha2::new(); + let arg_fields: Vec<_> = args + .iter() + .enumerate() + .map(|(idx, arg)| Field::new(format!("arg_{idx}"), arg.data_type(), true).into()) + .collect(); + let config_options = Arc::new(ConfigOptions::default()); + + c.bench_function(&format!("{name}/size={size}"), |b| { + b.iter(|| { + black_box( + sha2_func + .invoke_with_args(ScalarFunctionArgs { + args: args.to_vec(), + arg_fields: arg_fields.clone(), + number_rows: size, + return_field: Arc::new(Field::new("f", DataType::Utf8, true)), + config_options: Arc::clone(&config_options), + }) + .unwrap(), + ) + }) + }); +} + +fn criterion_benchmark(c: &mut Criterion) { + // Scalar benchmark (avoid array expansion) + let scalar_args = vec![ + ColumnarValue::Scalar(ScalarValue::Binary(Some(b"Spark".to_vec()))), + ColumnarValue::Scalar(ScalarValue::Int32(Some(256))), + ]; + run_benchmark(c, "sha2/scalar", 1, &scalar_args); + + let sizes = vec![1024, 4096, 8192]; + let null_density = 0.1; + + for &size in &sizes { + let values: ArrayRef = Arc::new(generate_binary_data(size, null_density)); + let bit_lengths: ArrayRef = Arc::new(Int32Array::from(vec![256; size])); + + let array_args = vec![ + ColumnarValue::Array(Arc::clone(&values)), + ColumnarValue::Array(Arc::clone(&bit_lengths)), + ]; + run_benchmark(c, "sha2/array_binary_256", size, &array_args); + + let array_scalar_args = vec![ + ColumnarValue::Array(Arc::clone(&values)), + ColumnarValue::Scalar(ScalarValue::Int32(Some(256))), + ]; + run_benchmark(c, "sha2/array_scalar_binary_256", size, &array_scalar_args); + } +} + +criterion_group!(benches, criterion_benchmark); +criterion_main!(benches); diff --git a/datafusion/spark/src/function/hash/sha2.rs b/datafusion/spark/src/function/hash/sha2.rs index a7ce5d7eb..2f01854d3 100644 --- a/datafusion/spark/src/function/hash/sha2.rs +++ b/datafusion/spark/src/function/hash/sha2.rs @@ -15,13 +15,15 @@ // specific language governing permissions and limitations // under the License. -use arrow::array::{ArrayRef, AsArray, BinaryArrayType, Int32Array, StringArray}; +use arrow::array::{ + ArrayRef, AsArray, BinaryArrayType, Int32Array, StringArray, new_null_array, +}; use arrow::datatypes::{DataType, Int32Type}; use datafusion_common::types::{ NativeType, logical_binary, logical_int32, logical_string, }; use datafusion_common::utils::take_function_args; -use datafusion_common::{Result, internal_err}; +use datafusion_common::{Result, ScalarValue, internal_err}; use datafusion_expr::{ Coercion, ColumnarValue, ScalarFunctionArgs, ScalarUDFImpl, Signature, TypeSignatureClass, Volatility, @@ -29,7 +31,6 @@ use datafusion_expr::{ use datafusion_functions::utils::make_scalar_function; use sha2::{self, Digest}; use std::any::Any; -use std::fmt::Write; use std::sync::Arc; /// Differs from DataFusion version in allowing array input for bit lengths, and @@ -87,7 +88,97 @@ impl ScalarUDFImpl for SparkSha2 { } fn invoke_with_args(&self, args: ScalarFunctionArgs) -> Result<ColumnarValue> { - make_scalar_function(sha2_impl, vec![])(&args.args) + let [values, bit_lengths] = take_function_args(self.name(), args.args.iter())?; + + match (values, bit_lengths) { + ( + ColumnarValue::Scalar(value_scalar), + ColumnarValue::Scalar(ScalarValue::Int32(Some(bit_length))), + ) => { + if value_scalar.is_null() { + return Ok(ColumnarValue::Scalar(ScalarValue::Utf8(None))); + } + + // Accept both Binary and Utf8 scalars (depending on coercion) + let bytes = match value_scalar { + ScalarValue::Binary(Some(b)) => b.as_slice(), + ScalarValue::LargeBinary(Some(b)) => b.as_slice(), + ScalarValue::BinaryView(Some(b)) => b.as_slice(), + ScalarValue::Utf8(Some(s)) + | ScalarValue::LargeUtf8(Some(s)) + | ScalarValue::Utf8View(Some(s)) => s.as_bytes(), + other => { + return internal_err!( + "Unsupported scalar datatype for sha2: {}", + other.data_type() + ); + } + }; + + let out = match bit_length { + 224 => { + let mut digest = sha2::Sha224::default(); + digest.update(bytes); + Some(hex_encode(digest.finalize())) + } + 0 | 256 => { + let mut digest = sha2::Sha256::default(); + digest.update(bytes); + Some(hex_encode(digest.finalize())) + } + 384 => { + let mut digest = sha2::Sha384::default(); + digest.update(bytes); + Some(hex_encode(digest.finalize())) + } + 512 => { + let mut digest = sha2::Sha512::default(); + digest.update(bytes); + Some(hex_encode(digest.finalize())) + } + _ => None, + }; + + Ok(ColumnarValue::Scalar(ScalarValue::Utf8(out))) + } + // Array values + scalar bit length (common case: sha2(col, 256)) + ( + ColumnarValue::Array(values_array), + ColumnarValue::Scalar(ScalarValue::Int32(Some(bit_length))), + ) => { + let output: ArrayRef = match values_array.data_type() { + DataType::Binary => sha2_binary_scalar_bitlen( + &values_array.as_binary::<i32>(), + *bit_length, + ), + DataType::LargeBinary => sha2_binary_scalar_bitlen( + &values_array.as_binary::<i64>(), + *bit_length, + ), + DataType::BinaryView => sha2_binary_scalar_bitlen( + &values_array.as_binary_view(), + *bit_length, + ), + dt => return internal_err!("Unsupported datatype for sha2: {dt}"), + }; + Ok(ColumnarValue::Array(output)) + } + ( + ColumnarValue::Scalar(_), + ColumnarValue::Scalar(ScalarValue::Int32(None)), + ) => Ok(ColumnarValue::Scalar(ScalarValue::Utf8(None))), + ( + ColumnarValue::Array(_), + ColumnarValue::Scalar(ScalarValue::Int32(None)), + ) => Ok(ColumnarValue::Array(new_null_array( + &DataType::Utf8, + args.number_rows, + ))), + _ => { + // Fallback to existing behavior for any array/mixed cases + make_scalar_function(sha2_impl, vec![])(&args.args) + } + } } } @@ -112,10 +203,31 @@ fn sha2_binary_impl<'a, BinaryArrType>( ) -> ArrayRef where BinaryArrType: BinaryArrayType<'a>, +{ + sha2_binary_bitlen_iter(values, bit_lengths.iter()) +} + +fn sha2_binary_scalar_bitlen<'a, BinaryArrType>( + values: &BinaryArrType, + bit_length: i32, +) -> ArrayRef +where + BinaryArrType: BinaryArrayType<'a>, +{ + sha2_binary_bitlen_iter(values, std::iter::repeat(Some(bit_length))) +} + +fn sha2_binary_bitlen_iter<'a, BinaryArrType, I>( + values: &BinaryArrType, + bit_lengths: I, +) -> ArrayRef +where + BinaryArrType: BinaryArrayType<'a>, + I: Iterator<Item = Option<i32>>, { let array = values .iter() - .zip(bit_lengths.iter()) + .zip(bit_lengths) .map(|(value, bit_length)| match (value, bit_length) { (Some(value), Some(224)) => { let mut digest = sha2::Sha224::default(); @@ -144,11 +256,18 @@ where Arc::new(array) } +const HEX_CHARS: [u8; 16] = *b"0123456789abcdef"; + +#[inline] fn hex_encode<T: AsRef<[u8]>>(data: T) -> String { - let mut s = String::with_capacity(data.as_ref().len() * 2); - for b in data.as_ref() { - // Writing to a string never errors, so we can unwrap here. - write!(&mut s, "{b:02x}").unwrap(); + let bytes = data.as_ref(); + let mut out = Vec::with_capacity(bytes.len() * 2); + for &b in bytes { + let hi = b >> 4; + let lo = b & 0x0F; + out.push(HEX_CHARS[hi as usize]); + out.push(HEX_CHARS[lo as usize]); } - s + // SAFETY: out contains only ASCII + unsafe { String::from_utf8_unchecked(out) } } --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
