alamb commented on code in PR #6965: URL: https://github.com/apache/arrow-datafusion/pull/6965#discussion_r1264069846
########## datafusion/core/src/physical_optimizer/global_sort_selection.rs: ########## @@ -1,94 +0,0 @@ -// 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. - -//! Select the efficient global sort implementation based on sort details. - -use std::sync::Arc; - -use crate::config::ConfigOptions; -use crate::error::Result; -use crate::physical_optimizer::PhysicalOptimizerRule; -use crate::physical_plan::sorts::sort::SortExec; -use crate::physical_plan::sorts::sort_preserving_merge::SortPreservingMergeExec; -use crate::physical_plan::ExecutionPlan; -use datafusion_common::tree_node::{Transformed, TreeNode}; - -/// Currently for a sort operator, if -/// - there are more than one input partitions -/// - and there's some limit which can be pushed down to each of its input partitions -/// then [SortPreservingMergeExec] with local sort with a limit pushed down will be preferred; -/// Otherwise, the normal global sort [SortExec] will be used. -/// Later more intelligent statistics-based decision can also be introduced. -/// For example, for a small data set, the global sort may be efficient enough -#[derive(Default)] -pub struct GlobalSortSelection {} - -impl GlobalSortSelection { - #[allow(missing_docs)] - pub fn new() -> Self { - Self {} - } -} - -impl PhysicalOptimizerRule for GlobalSortSelection { - fn optimize( - &self, - plan: Arc<dyn ExecutionPlan>, - config: &ConfigOptions, - ) -> Result<Arc<dyn ExecutionPlan>> { - plan.transform_up(&|plan| { - let transformed = - plan.as_any() - .downcast_ref::<SortExec>() - .and_then(|sort_exec| { - if sort_exec.input().output_partitioning().partition_count() > 1 - // It's already preserving the partitioning so that it can be regarded as a local sort - && !sort_exec.preserve_partitioning() - && (sort_exec.fetch().is_some() || config.optimizer.repartition_sorts) - { - let sort = SortExec::new( - sort_exec.expr().to_vec(), - sort_exec.input().clone() - ) - .with_fetch(sort_exec.fetch()) - .with_preserve_partitioning(true); - let global_sort: Arc<dyn ExecutionPlan> = - Arc::new(SortPreservingMergeExec::new( - sort_exec.expr().to_vec(), - Arc::new(sort), - ).with_fetch(sort_exec.fetch())); - Some(global_sort) - } else { - None - } - }); - Ok(if let Some(transformed) = transformed { - Transformed::Yes(transformed) - } else { - Transformed::No(plan) - }) - }) - } - - fn name(&self) -> &str { Review Comment: it is interesting that there were no specific tests for this module -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
