radmirnovii commented on code in PR #24489: URL: https://github.com/apache/datafusion/pull/24489#discussion_r3878006149
########## datafusion/optimizer/benches/simplify_function_over_case.rs: ########## @@ -0,0 +1,172 @@ +// 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. + +//! Microbenchmarks for a scalar function applied to a CASE with literal +//! branches: plan-time simplifier cost over N branches, and per-batch +//! evaluation cost of the (2-branch) expression after the standard +//! simplification pipeline. + +use arrow::array::BooleanArray; +use arrow::datatypes::{DataType, Field, Schema}; +use arrow::record_batch::RecordBatch; +use criterion::{BenchmarkId, Criterion, criterion_group, criterion_main}; +use datafusion_common::{DFSchema, Result, ScalarValue}; +use datafusion_expr::execution_props::ExecutionProps; +use datafusion_expr::expr::ScalarFunction; +use datafusion_expr::physical_planning_context::PhysicalPlanningContext; +use datafusion_expr::simplify::SimplifyContext; +use datafusion_expr::{ + Case, ColumnarValue, Expr, ScalarFunctionArgs, ScalarUDF, ScalarUDFImpl, Signature, + Volatility, col, lit, +}; +use datafusion_optimizer::simplify_expressions::ExprSimplifier; +use datafusion_physical_expr::create_physical_expr; +use std::hint::black_box; +use std::sync::Arc; + +/// A deliberately expensive immutable `&str -> i64` function standing in for +/// real parse-heavy work (timestamp/format parsing, regex compilation). +#[derive(Debug, PartialEq, Eq, Hash)] +struct ExpensiveParse { + signature: Signature, +} + +impl ExpensiveParse { + fn new() -> Self { + Self { + signature: Signature::variadic_any(Volatility::Immutable), + } + } +} + +fn expensive_parse_str(s: &str) -> i64 { + let mut acc: i64 = 0; + for _round in 0..100 { + for b in s.bytes() { + acc = acc.wrapping_mul(31).wrapping_add(i64::from(b)); + } + } + acc +} + +impl ScalarUDFImpl for ExpensiveParse { + fn name(&self) -> &str { + "expensive_parse" + } + + fn signature(&self) -> &Signature { + &self.signature + } + + fn return_type(&self, _arg_types: &[DataType]) -> Result<DataType> { + Ok(DataType::Int64) + } + + fn invoke_with_args(&self, args: ScalarFunctionArgs) -> Result<ColumnarValue> { + match &args.args[0] { + ColumnarValue::Scalar(ScalarValue::Utf8(v)) => Ok(ColumnarValue::Scalar( + ScalarValue::Int64(v.as_deref().map(expensive_parse_str)), + )), + ColumnarValue::Array(array) => { + let strings = arrow::array::cast::as_string_array(array); + let out: arrow::array::Int64Array = + strings.iter().map(|v| v.map(expensive_parse_str)).collect(); + Ok(ColumnarValue::Array(Arc::new(out))) + } + _ => datafusion_common::exec_err!("expensive_parse: unsupported argument"), + } + } +} + +/// `f(CASE WHEN flag THEN 'b0' WHEN ... ELSE 'e' END)` with `branches` WHEN arms. +fn function_over_case(branches: usize) -> Expr { + let case = Expr::Case(Case::new( + None, + (0..branches) + .map(|i| { + ( + Box::new(col("flag")), + Box::new(lit(format!("branch-value-{i}"))), + ) + }) + .collect(), + Some(Box::new(lit("else-value"))), + )); + Expr::ScalarFunction(ScalarFunction::new_udf( + Arc::new(ScalarUDF::new_from_impl(ExpensiveParse::new())), + vec![case], + )) +} + +fn schema() -> Arc<DFSchema> { + Arc::new( + DFSchema::try_from(Schema::new(vec![Field::new( + "flag", + DataType::Boolean, + false, + )])) + .unwrap(), + ) +} + +fn simplifier(schema: Arc<DFSchema>) -> ExprSimplifier { + ExprSimplifier::new(SimplifyContext::builder().with_schema(schema).build()) +} + +fn bench_simplify(c: &mut Criterion) { + let mut group = c.benchmark_group("simplify_function_over_case/simplify"); + for branches in [2usize, 8, 32] { + let expr = function_over_case(branches); + let simplifier = simplifier(schema()); + group.bench_with_input( + BenchmarkId::from_parameter(branches), + &expr, + |b, expr| { + b.iter_batched( + || expr.clone(), + |expr| black_box(simplifier.simplify(expr).unwrap()), + criterion::BatchSize::SmallInput, + ) + }, + ); + } + group.finish(); +} + +fn bench_evaluate(c: &mut Criterion) { + let df_schema = schema(); + let rows = 8192; + let flags = BooleanArray::from_iter((0..rows).map(|i| Some(i % 2 == 0))); + let batch = + RecordBatch::try_new(Arc::clone(df_schema.inner()), vec![Arc::new(flags)]) + .unwrap(); + + let expr = simplifier(Arc::clone(&df_schema)) + .simplify(function_over_case(2)) + .unwrap(); Review Comment: Added. ########## datafusion/optimizer/benches/simplify_function_over_case.rs: ########## @@ -0,0 +1,172 @@ +// 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. + +//! Microbenchmarks for a scalar function applied to a CASE with literal +//! branches: plan-time simplifier cost over N branches, and per-batch +//! evaluation cost of the (2-branch) expression after the standard +//! simplification pipeline. + +use arrow::array::BooleanArray; +use arrow::datatypes::{DataType, Field, Schema}; +use arrow::record_batch::RecordBatch; +use criterion::{BenchmarkId, Criterion, criterion_group, criterion_main}; +use datafusion_common::{DFSchema, Result, ScalarValue}; +use datafusion_expr::execution_props::ExecutionProps; +use datafusion_expr::expr::ScalarFunction; +use datafusion_expr::physical_planning_context::PhysicalPlanningContext; +use datafusion_expr::simplify::SimplifyContext; +use datafusion_expr::{ + Case, ColumnarValue, Expr, ScalarFunctionArgs, ScalarUDF, ScalarUDFImpl, Signature, + Volatility, col, lit, +}; +use datafusion_optimizer::simplify_expressions::ExprSimplifier; +use datafusion_physical_expr::create_physical_expr; +use std::hint::black_box; +use std::sync::Arc; + +/// A deliberately expensive immutable `&str -> i64` function standing in for +/// real parse-heavy work (timestamp/format parsing, regex compilation). +#[derive(Debug, PartialEq, Eq, Hash)] +struct ExpensiveParse { + signature: Signature, +} + +impl ExpensiveParse { + fn new() -> Self { + Self { + signature: Signature::variadic_any(Volatility::Immutable), + } + } +} + +fn expensive_parse_str(s: &str) -> i64 { + let mut acc: i64 = 0; + for _round in 0..100 { + for b in s.bytes() { + acc = acc.wrapping_mul(31).wrapping_add(i64::from(b)); + } + } + acc +} + +impl ScalarUDFImpl for ExpensiveParse { + fn name(&self) -> &str { + "expensive_parse" + } + + fn signature(&self) -> &Signature { + &self.signature + } + + fn return_type(&self, _arg_types: &[DataType]) -> Result<DataType> { + Ok(DataType::Int64) + } + + fn invoke_with_args(&self, args: ScalarFunctionArgs) -> Result<ColumnarValue> { + match &args.args[0] { + ColumnarValue::Scalar(ScalarValue::Utf8(v)) => Ok(ColumnarValue::Scalar( + ScalarValue::Int64(v.as_deref().map(expensive_parse_str)), + )), + ColumnarValue::Array(array) => { + let strings = arrow::array::cast::as_string_array(array); + let out: arrow::array::Int64Array = + strings.iter().map(|v| v.map(expensive_parse_str)).collect(); + Ok(ColumnarValue::Array(Arc::new(out))) + } + _ => datafusion_common::exec_err!("expensive_parse: unsupported argument"), + } + } +} + +/// `f(CASE WHEN flag THEN 'b0' WHEN ... ELSE 'e' END)` with `branches` WHEN arms. +fn function_over_case(branches: usize) -> Expr { + let case = Expr::Case(Case::new( + None, + (0..branches) + .map(|i| { + ( + Box::new(col("flag")), + Box::new(lit(format!("branch-value-{i}"))), + ) + }) + .collect(), + Some(Box::new(lit("else-value"))), + )); + Expr::ScalarFunction(ScalarFunction::new_udf( + Arc::new(ScalarUDF::new_from_impl(ExpensiveParse::new())), + vec![case], + )) +} + +fn schema() -> Arc<DFSchema> { + Arc::new( + DFSchema::try_from(Schema::new(vec![Field::new( + "flag", + DataType::Boolean, + false, + )])) + .unwrap(), + ) +} + +fn simplifier(schema: Arc<DFSchema>) -> ExprSimplifier { + ExprSimplifier::new(SimplifyContext::builder().with_schema(schema).build()) +} + +fn bench_simplify(c: &mut Criterion) { + let mut group = c.benchmark_group("simplify_function_over_case/simplify"); + for branches in [2usize, 8, 32] { + let expr = function_over_case(branches); + let simplifier = simplifier(schema()); + group.bench_with_input( + BenchmarkId::from_parameter(branches), + &expr, + |b, expr| { + b.iter_batched( + || expr.clone(), + |expr| black_box(simplifier.simplify(expr).unwrap()), + criterion::BatchSize::SmallInput, + ) + }, + ); + } + group.finish(); +} + +fn bench_evaluate(c: &mut Criterion) { + let df_schema = schema(); + let rows = 8192; Review Comment: Left as is, for the reason you give. -- This is an automated message from the Apache Git Service. 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