From 63b8cd35e294809e20ed007dc94a21d2e2b8e148 Mon Sep 17 00:00:00 2001 From: Edd Robinson Date: Tue, 6 Jul 2021 13:04:33 +0100 Subject: [PATCH 1/4] test: add benchmarks for SortPreservingMergeExec --- datafusion/Cargo.toml | 4 + datafusion/benches/physical_plan.rs | 176 ++++++++++++++++++++++++++++ 2 files changed, 180 insertions(+) create mode 100644 datafusion/benches/physical_plan.rs diff --git a/datafusion/Cargo.toml b/datafusion/Cargo.toml index f1a77741064e4..845de6213f4d3 100644 --- a/datafusion/Cargo.toml +++ b/datafusion/Cargo.toml @@ -95,3 +95,7 @@ harness = false [[bench]] name = "scalar" harness = false + +[[bench]] +name = "physical_plan" +harness = false \ No newline at end of file diff --git a/datafusion/benches/physical_plan.rs b/datafusion/benches/physical_plan.rs new file mode 100644 index 0000000000000..c71b8232c3303 --- /dev/null +++ b/datafusion/benches/physical_plan.rs @@ -0,0 +1,176 @@ +// 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. + +#[macro_use] +extern crate criterion; +use criterion::{BatchSize, Criterion}; +extern crate arrow; +extern crate datafusion; + +use std::{iter::FromIterator, sync::Arc}; + +use arrow::{ + array::{ArrayRef, Int64Array, StringArray}, + record_batch::RecordBatch, +}; +use tokio::runtime::Runtime; + +use datafusion::physical_plan::{ + collect, + expressions::{col, PhysicalSortExpr}, + memory::MemoryExec, + sort_preserving_merge::SortPreservingMergeExec, +}; + +// Initialise the operator using the provided record batches and the sort key +// as inputs. All record batches must have the same schema. +fn sort_preserving_merge_operator(batches: Vec, sort: &[&str]) { + let schema = batches[0].schema(); + + let sort = sort + .iter() + .map(|name| PhysicalSortExpr { + expr: col(name, &schema).unwrap(), + options: Default::default(), + }) + .collect::>(); + + let exec = MemoryExec::try_new( + &batches.into_iter().map(|rb| vec![rb]).collect::>(), + schema, + None, + ) + .unwrap(); + let merge = Arc::new(SortPreservingMergeExec::new(sort, Arc::new(exec), 10000)); + + let rt = Runtime::new().unwrap(); + rt.block_on(collect(merge)).unwrap(); +} + +// Produces `n` record batches of row size `m`. Each record batch will have +// identical contents except for if the `batch_offset` is set. In that case the +// values for column "d" in each subsequent record batch will be offset in +// value. +// +// The `rows_per_key` value controls how many rows are generated per "key", +// which is defined as columns a, b and c. +fn batches( + n: usize, + m: usize, + rows_per_sort_key: usize, + batch_offset: usize, +) -> Vec { + let mut rbs = Vec::with_capacity(n); + let mut curr_batch_offset = 0; + + for _ in 0..n { + let mut col_a = Vec::with_capacity(m); + let mut col_b = Vec::with_capacity(m); + let mut col_c = Vec::with_capacity(m); + let mut col_d = Vec::with_capacity(m); + + let mut j = 0; + let mut current_rows_per_sort_key = 0; + + for i in 0..m { + if current_rows_per_sort_key == rows_per_sort_key { + current_rows_per_sort_key = 0; + j = i; + } + + col_a.push(Some(format!("a-{:?}", j))); + col_b.push(Some(format!("b-{:?}", j))); + col_c.push(Some(format!("c-{:?}", j))); + col_d.push(Some((i + curr_batch_offset) as i64)); + + current_rows_per_sort_key += 1; + } + + col_a.sort(); + col_b.sort(); + col_c.sort(); + + let col_a: ArrayRef = Arc::new(StringArray::from_iter(col_a)); + let col_b: ArrayRef = Arc::new(StringArray::from_iter(col_b)); + let col_c: ArrayRef = Arc::new(StringArray::from_iter(col_c)); + let col_d: ArrayRef = Arc::new(Int64Array::from(col_d)); + + let rb = RecordBatch::try_from_iter(vec![ + ("a", col_a), + ("b", col_b), + ("c", col_c), + ("d", col_d), + ]) + .unwrap(); + rbs.push(rb); + + curr_batch_offset += batch_offset; + } + + rbs +} + +fn criterion_benchmark(c: &mut Criterion) { + let small_batch = batches(1, 100, 10, 0).remove(0); + let large_batch = batches(1, 1000, 1, 0).remove(0); + + let benches = vec![ + // Two batches with identical rows. They will need to be merged together + // with one row from each batch being taken until both batches are + // drained. + ("interleave_batches", batches(2, 1000, 10, 1)), + // Two batches with a small overlapping region of rows for each unique + // sort key. + ("merge_batches_some_overlap_small", batches(2, 1000, 10, 5)), + // Two batches with a large overlapping region of rows for each unique + // sort key. + ( + "merge_batches_some_overlap_large", + batches(2, 1000, 250, 125), + ), + // Two batches with no overlapping region of rows for each unique + // sort key. For a given unique sort key all rows are drained from one + // batch, then all the rows for the same key from the second batch. + // This repeats until all rows are drained. There are a small number of + // rows (10) for each unique sort key. + ("merge_batches_no_overlap_small", batches(2, 1000, 10, 12)), + // As above but this time there are a larger number of rows (250) for + // each unique sort key - still no overlaps. + ("merge_batches_no_overlap_large", batches(2, 1000, 250, 252)), + // Merges two batches where one batch is significantly larger than the + // other. + ( + "merge_batches_small_into_large", + vec![large_batch, small_batch], + ), + ]; + + for (name, input) in benches { + c.bench_function(name, move |b| { + b.iter_batched( + || input.clone(), + |input| { + sort_preserving_merge_operator(input, &["a", "b", "c", "d"]); + }, + BatchSize::LargeInput, + ) + }); + } +} + +criterion_group!(benches, criterion_benchmark); +criterion_main!(benches); From 8f285c7062ab92fd127cc321e108e090a5b9bf72 Mon Sep 17 00:00:00 2001 From: Edd Robinson Date: Tue, 6 Jul 2021 17:02:42 +0100 Subject: [PATCH 2/4] perf: minimise array data extend calls MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The `SortPreservingMergeStream` operator merges two streams together by creating an output record batch that is build from the contents of the input. Previously each row of input would be pushed into the output sink even if though the API supports pushing batches of rows. This commit implements the logic to push batches of rows from inputs where possible. Performance benchmarks show an improvement of between 3-12%. ``` group master pr ----- ------ -- interleave_batches 1.04 637.5±51.84µs ? ?/sec 1.00 615.5±12.13µs ? ?/sec merge_batches_no_overlap_large 1.12 454.9±2.90µs ? ?/sec 1.00 404.9±10.94µs ? ?/sec merge_batches_no_overlap_small 1.14 485.1±6.67µs ? ?/sec 1.00 425.7±9.33µs ? ?/sec merge_batches_small_into_large 1.14 263.0±8.85µs ? ?/sec 1.00 229.7±5.23µs ? ?/sec merge_batches_some_overlap_large 1.05 532.5±8.33µs ? ?/sec 1.00 508.3±14.24µs ? ?/sec merge_batches_some_overlap_small 1.06 546.9±12.82µs ? ?/sec 1.00 516.9±13.20µs ? ?/sec ``` --- .../physical_plan/sort_preserving_merge.rs | 56 +++++++++++++------ 1 file changed, 38 insertions(+), 18 deletions(-) diff --git a/datafusion/src/physical_plan/sort_preserving_merge.rs b/datafusion/src/physical_plan/sort_preserving_merge.rs index 316f0509960dd..76da856c6ed18 100644 --- a/datafusion/src/physical_plan/sort_preserving_merge.rs +++ b/datafusion/src/physical_plan/sort_preserving_merge.rs @@ -24,22 +24,23 @@ use std::pin::Pin; use std::sync::Arc; use std::task::{Context, Poll}; -use arrow::array::{ArrayRef, MutableArrayData}; -use arrow::compute::SortOptions; +use arrow::{ + array::{make_array as make_arrow_array, ArrayRef, MutableArrayData}, + compute::SortOptions, + datatypes::SchemaRef, + error::{ArrowError, Result as ArrowResult}, + record_batch::RecordBatch, +}; use async_trait::async_trait; use futures::channel::mpsc; use futures::stream::FusedStream; use futures::{Stream, StreamExt}; -use crate::arrow::datatypes::SchemaRef; -use crate::arrow::error::ArrowError; -use crate::arrow::{error::Result as ArrowResult, record_batch::RecordBatch}; use crate::error::{DataFusionError, Result}; -use crate::physical_plan::common::spawn_execution; -use crate::physical_plan::expressions::PhysicalSortExpr; use crate::physical_plan::{ - DisplayFormatType, Distribution, ExecutionPlan, Partitioning, PhysicalExpr, - RecordBatchStream, SendableRecordBatchStream, + common::spawn_execution, expressions::PhysicalSortExpr, DisplayFormatType, + Distribution, ExecutionPlan, Partitioning, PhysicalExpr, RecordBatchStream, + SendableRecordBatchStream, }; /// Sort preserving merge execution plan @@ -425,19 +426,38 @@ impl SortPreservingMergeStream { self.in_progress.len(), ); - for row_index in &self.in_progress { - let buffer_idx = + if self.in_progress.is_empty() { + return make_arrow_array(array_data.freeze()); + } + + let first = &self.in_progress[0]; + let mut buffer_idx = + stream_to_buffer_idx[first.stream_idx] + first.cursor_idx; + let mut start_row_idx = first.row_idx; + let mut end_row_idx = start_row_idx + 1; + + for row_index in self.in_progress.iter().skip(1) { + let next_buffer_idx = stream_to_buffer_idx[row_index.stream_idx] + row_index.cursor_idx; - // TODO: Coalesce contiguous writes - array_data.extend( - buffer_idx, - row_index.row_idx, - row_index.row_idx + 1, - ); + if next_buffer_idx == buffer_idx && row_index.row_idx == end_row_idx { + // subsequent row in same batch + end_row_idx += 1; + continue; + } + + // emit current batch of rows for current buffer + array_data.extend(buffer_idx, start_row_idx, end_row_idx); + + // start new batch of rows + buffer_idx = next_buffer_idx; + start_row_idx = row_index.row_idx; + end_row_idx = start_row_idx + 1; } - arrow::array::make_array(array_data.freeze()) + // emit final batch of rows + array_data.extend(buffer_idx, start_row_idx, end_row_idx); + make_arrow_array(array_data.freeze()) }) .collect(); From 665a0593914cedad81ba6ad8f12da4a4abd69237 Mon Sep 17 00:00:00 2001 From: Edd Robinson Date: Tue, 6 Jul 2021 18:11:04 +0100 Subject: [PATCH 3/4] test: more test coverage --- .../physical_plan/sort_preserving_merge.rs | 146 +++++++++++++++--- 1 file changed, 123 insertions(+), 23 deletions(-) diff --git a/datafusion/src/physical_plan/sort_preserving_merge.rs b/datafusion/src/physical_plan/sort_preserving_merge.rs index 76da856c6ed18..0949c3c6a8cf6 100644 --- a/datafusion/src/physical_plan/sort_preserving_merge.rs +++ b/datafusion/src/physical_plan/sort_preserving_merge.rs @@ -575,7 +575,54 @@ mod tests { use tokio_stream::StreamExt; #[tokio::test] - async fn test_merge() { + async fn test_merge_interleave() { + let a: ArrayRef = Arc::new(Int32Array::from(vec![1, 2, 7, 9, 3])); + let b: ArrayRef = Arc::new(StringArray::from_iter(vec![ + Some("a"), + Some("c"), + Some("e"), + Some("g"), + Some("j"), + ])); + let c: ArrayRef = Arc::new(TimestampNanosecondArray::from(vec![8, 7, 6, 5, 8])); + let b1 = RecordBatch::try_from_iter(vec![("a", a), ("b", b), ("c", c)]).unwrap(); + + let a: ArrayRef = Arc::new(Int32Array::from(vec![10, 20, 70, 90, 30])); + let b: ArrayRef = Arc::new(StringArray::from_iter(vec![ + Some("b"), + Some("d"), + Some("f"), + Some("h"), + Some("j"), + ])); + let c: ArrayRef = Arc::new(TimestampNanosecondArray::from(vec![4, 6, 2, 2, 6])); + let b2 = RecordBatch::try_from_iter(vec![("a", a), ("b", b), ("c", c)]).unwrap(); + + _test_merge( + b1, + b2, + &[ + "+----+---+-------------------------------+", + "| a | b | c |", + "+----+---+-------------------------------+", + "| 1 | a | 1970-01-01 00:00:00.000000008 |", + "| 10 | b | 1970-01-01 00:00:00.000000004 |", + "| 2 | c | 1970-01-01 00:00:00.000000007 |", + "| 20 | d | 1970-01-01 00:00:00.000000006 |", + "| 7 | e | 1970-01-01 00:00:00.000000006 |", + "| 70 | f | 1970-01-01 00:00:00.000000002 |", + "| 9 | g | 1970-01-01 00:00:00.000000005 |", + "| 90 | h | 1970-01-01 00:00:00.000000002 |", + "| 30 | j | 1970-01-01 00:00:00.000000006 |", // input b2 before b1 + "| 3 | j | 1970-01-01 00:00:00.000000008 |", + "+----+---+-------------------------------+", + ], + ) + .await; + } + + #[tokio::test] + async fn test_merge_some_overlap() { let a: ArrayRef = Arc::new(Int32Array::from(vec![1, 2, 7, 9, 3])); let b: ArrayRef = Arc::new(StringArray::from_iter(vec![ Some("a"), @@ -584,21 +631,92 @@ mod tests { Some("d"), Some("e"), ])); - let c: ArrayRef = Arc::new(TimestampNanosecondArray::from(vec![8, 7, 6, 5, 4])); + let c: ArrayRef = Arc::new(TimestampNanosecondArray::from(vec![8, 7, 6, 5, 8])); let b1 = RecordBatch::try_from_iter(vec![("a", a), ("b", b), ("c", c)]).unwrap(); - let a: ArrayRef = Arc::new(Int32Array::from(vec![1, 2, 3, 4, 5])); + let a: ArrayRef = Arc::new(Int32Array::from(vec![70, 90, 30, 100, 110])); let b: ArrayRef = Arc::new(StringArray::from_iter(vec![ + Some("c"), Some("d"), Some("e"), + Some("f"), + Some("g"), + ])); + let c: ArrayRef = Arc::new(TimestampNanosecondArray::from(vec![4, 6, 2, 2, 6])); + let b2 = RecordBatch::try_from_iter(vec![("a", a), ("b", b), ("c", c)]).unwrap(); + + _test_merge( + b1, + b2, + &[ + "+-----+---+-------------------------------+", + "| a | b | c |", + "+-----+---+-------------------------------+", + "| 1 | a | 1970-01-01 00:00:00.000000008 |", + "| 2 | b | 1970-01-01 00:00:00.000000007 |", + "| 70 | c | 1970-01-01 00:00:00.000000004 |", + "| 7 | c | 1970-01-01 00:00:00.000000006 |", + "| 9 | d | 1970-01-01 00:00:00.000000005 |", + "| 90 | d | 1970-01-01 00:00:00.000000006 |", + "| 30 | e | 1970-01-01 00:00:00.000000002 |", + "| 3 | e | 1970-01-01 00:00:00.000000008 |", + "| 100 | f | 1970-01-01 00:00:00.000000002 |", + "| 110 | g | 1970-01-01 00:00:00.000000006 |", + "+-----+---+-------------------------------+", + ], + ) + .await; + } + + #[tokio::test] + async fn test_merge_no_overlap() { + let a: ArrayRef = Arc::new(Int32Array::from(vec![1, 2, 7, 9, 3])); + let b: ArrayRef = Arc::new(StringArray::from_iter(vec![ + Some("a"), + Some("b"), + Some("c"), + Some("d"), + Some("e"), + ])); + let c: ArrayRef = Arc::new(TimestampNanosecondArray::from(vec![8, 7, 6, 5, 8])); + let b1 = RecordBatch::try_from_iter(vec![("a", a), ("b", b), ("c", c)]).unwrap(); + + let a: ArrayRef = Arc::new(Int32Array::from(vec![10, 20, 70, 90, 30])); + let b: ArrayRef = Arc::new(StringArray::from_iter(vec![ + Some("f"), Some("g"), Some("h"), Some("i"), + Some("j"), ])); let c: ArrayRef = Arc::new(TimestampNanosecondArray::from(vec![4, 6, 2, 2, 6])); let b2 = RecordBatch::try_from_iter(vec![("a", a), ("b", b), ("c", c)]).unwrap(); - let schema = b1.schema(); + _test_merge( + b1, + b2, + &[ + "+----+---+-------------------------------+", + "| a | b | c |", + "+----+---+-------------------------------+", + "| 1 | a | 1970-01-01 00:00:00.000000008 |", + "| 2 | b | 1970-01-01 00:00:00.000000007 |", + "| 7 | c | 1970-01-01 00:00:00.000000006 |", + "| 9 | d | 1970-01-01 00:00:00.000000005 |", + "| 3 | e | 1970-01-01 00:00:00.000000008 |", + "| 10 | f | 1970-01-01 00:00:00.000000004 |", + "| 20 | g | 1970-01-01 00:00:00.000000006 |", + "| 70 | h | 1970-01-01 00:00:00.000000002 |", + "| 90 | i | 1970-01-01 00:00:00.000000002 |", + "| 30 | j | 1970-01-01 00:00:00.000000006 |", + "+----+---+-------------------------------+", + ], + ) + .await; + } + + async fn _test_merge(b1: RecordBatch, b2: RecordBatch, exp: &[&str]) { + let schema = b1.schema(); let sort = vec![ PhysicalSortExpr { expr: col("b", &schema).unwrap(), @@ -615,25 +733,7 @@ mod tests { let collected = collect(merge).await.unwrap(); assert_eq!(collected.len(), 1); - assert_batches_eq!( - &[ - "+---+---+-------------------------------+", - "| a | b | c |", - "+---+---+-------------------------------+", - "| 1 | a | 1970-01-01 00:00:00.000000008 |", - "| 2 | b | 1970-01-01 00:00:00.000000007 |", - "| 7 | c | 1970-01-01 00:00:00.000000006 |", - "| 1 | d | 1970-01-01 00:00:00.000000004 |", - "| 9 | d | 1970-01-01 00:00:00.000000005 |", - "| 3 | e | 1970-01-01 00:00:00.000000004 |", - "| 2 | e | 1970-01-01 00:00:00.000000006 |", - "| 3 | g | 1970-01-01 00:00:00.000000002 |", - "| 4 | h | 1970-01-01 00:00:00.000000002 |", - "| 5 | i | 1970-01-01 00:00:00.000000006 |", - "+---+---+-------------------------------+", - ], - collected.as_slice() - ); + assert_batches_eq!(exp, collected.as_slice()); } async fn sorted_merge( From 5f905c212be9495fe072da15251ea8388a1c89ec Mon Sep 17 00:00:00 2001 From: Edd Robinson Date: Wed, 7 Jul 2021 17:09:49 +0100 Subject: [PATCH 4/4] refactor: update batch size --- datafusion/benches/physical_plan.rs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/datafusion/benches/physical_plan.rs b/datafusion/benches/physical_plan.rs index c71b8232c3303..9222ae131b8ff 100644 --- a/datafusion/benches/physical_plan.rs +++ b/datafusion/benches/physical_plan.rs @@ -55,7 +55,7 @@ fn sort_preserving_merge_operator(batches: Vec, sort: &[&str]) { None, ) .unwrap(); - let merge = Arc::new(SortPreservingMergeExec::new(sort, Arc::new(exec), 10000)); + let merge = Arc::new(SortPreservingMergeExec::new(sort, Arc::new(exec), 8192)); let rt = Runtime::new().unwrap(); rt.block_on(collect(merge)).unwrap();