UBarney commented on code in PR #21383:
URL: https://github.com/apache/datafusion/pull/21383#discussion_r3037731579
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datafusion/functions-aggregate/src/first_last.rs:
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@@ -831,6 +830,8 @@ pub struct FirstValueAccumulator {
orderings: Vec<ScalarValue>,
// Stores the applicable ordering requirement.
ordering_req: LexOrdering,
+ // derived from `ordering_req`.
+ sort_options: Vec<SortOptions>,
Review Comment:
Since these changes are for performance optimization, should we add some
benchmarks for `FirstValueAccumulator` to quantify the improvement and prevent
future regressions?
##########
datafusion/functions-aggregate/benches/first_last.rs:
##########
@@ -0,0 +1,194 @@
+// 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 std::hint::black_box;
+use std::sync::Arc;
+
+use arrow::array::{ArrayRef, BooleanArray};
+use arrow::compute::SortOptions;
+use arrow::datatypes::{DataType, Field, Int64Type, Schema};
+use arrow::util::bench_util::{create_boolean_array, create_primitive_array};
+
+use datafusion_expr::{
+ AggregateUDFImpl, EmitTo, GroupsAccumulator, function::AccumulatorArgs,
+};
+use datafusion_functions_aggregate::first_last::{FirstValue, LastValue};
+use datafusion_physical_expr::PhysicalSortExpr;
+use datafusion_physical_expr::expressions::col;
+
+use criterion::{Criterion, criterion_group, criterion_main};
+
+fn prepare_groups_accumulator(is_first: bool) -> Box<dyn GroupsAccumulator> {
+ let schema = Arc::new(Schema::new(vec![
+ Field::new("value", DataType::Int64, true),
+ Field::new("ord", DataType::Int64, true),
+ ]));
+
+ let order_expr = col("ord", &schema).unwrap();
+ let sort_expr = PhysicalSortExpr {
+ expr: order_expr,
+ options: SortOptions::default(),
+ };
+
+ let value_field: Arc<Field> = Field::new("value", DataType::Int64,
true).into();
+ let accumulator_args = AccumulatorArgs {
+ return_field: Arc::clone(&value_field),
+ schema: &schema,
+ expr_fields: &[value_field],
+ ignore_nulls: false,
+ order_bys: std::slice::from_ref(&sort_expr),
+ is_reversed: false,
+ name: if is_first {
+ "FIRST_VALUE(value ORDER BY ord)"
+ } else {
+ "LAST_VALUE(value ORDER BY ord)"
+ },
+ is_distinct: false,
+ exprs: &[col("value", &schema).unwrap()],
+ };
+
+ if is_first {
+ FirstValue::new()
+ .create_groups_accumulator(accumulator_args)
+ .unwrap()
+ } else {
+ LastValue::new()
+ .create_groups_accumulator(accumulator_args)
+ .unwrap()
+ }
+}
+
+#[expect(clippy::needless_pass_by_value)]
+fn convert_to_state_bench(
+ c: &mut Criterion,
+ is_first: bool,
+ name: &str,
+ values: ArrayRef,
+ opt_filter: Option<&BooleanArray>,
+) {
+ c.bench_function(name, |b| {
+ b.iter(|| {
+ let accumulator = prepare_groups_accumulator(is_first);
+ black_box(
+ accumulator
+ .convert_to_state(std::slice::from_ref(&values),
opt_filter)
Review Comment:
Why are we benchmarking `convert_to_state` here? Since its implementation
hasn't changed in this PR, I'm curious about the motivation.
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