query/optimizer/
remove_duplicate.rs

1// Copyright 2023 Greptime Team
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15use std::sync::Arc;
16
17use datafusion::config::ConfigOptions;
18use datafusion::physical_optimizer::PhysicalOptimizerRule;
19use datafusion::physical_plan::repartition::RepartitionExec;
20use datafusion::physical_plan::{ChildrenPropertiesMode, ExecutionPlan, ReplaceChildrenOptions};
21use datafusion_common::Result as DfResult;
22use datafusion_common::tree_node::{Transformed, TreeNode};
23
24/// This is [PhysicalOptimizerRule] to remove duplicate physical plans such as two
25/// adjoining [RepartitionExec]. They won't have any effect
26/// if one runs right after another.
27///
28/// This rule is expected to be run in the final stage of the optimization process.
29#[derive(Debug)]
30pub struct RemoveDuplicate;
31
32impl PhysicalOptimizerRule for RemoveDuplicate {
33    fn optimize(
34        &self,
35        plan: Arc<dyn ExecutionPlan>,
36        _config: &ConfigOptions,
37    ) -> DfResult<Arc<dyn ExecutionPlan>> {
38        let result = plan
39            .transform_down(|plan| {
40                if plan.is::<RepartitionExec>() {
41                    // check child
42                    let child = plan.children()[0].clone();
43                    if child.is::<RepartitionExec>() {
44                        // remove child
45                        let grand_child = child.children()[0].clone();
46                        let new_plan = plan.replace_children(
47                            vec![grand_child],
48                            ReplaceChildrenOptions::new(ChildrenPropertiesMode::Recompute),
49                        )?;
50                        return Ok(Transformed::yes(new_plan));
51                    }
52                }
53
54                Ok(Transformed::no(plan))
55            })?
56            .data;
57        Ok(result)
58    }
59
60    fn name(&self) -> &str {
61        "RemoveDuplicateRule"
62    }
63
64    fn schema_check(&self) -> bool {
65        true
66    }
67}
query/optimizer/remove_duplicate.rs

query/optimizer/
remove_duplicate.rs
