risingwave_frontend/optimizer/rule/
project_join_merge_rule.rs

1// Copyright 2025 RisingWave Labs
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 super::super::plan_node::*;
16use super::{BoxedRule, Rule};
17pub struct ProjectJoinMergeRule {}
18
19impl ProjectJoinMergeRule {
20    pub fn create() -> BoxedRule {
21        Box::new(Self {})
22    }
23}
24
25impl Rule for ProjectJoinMergeRule {
26    fn apply(&self, plan: PlanRef) -> Option<PlanRef> {
27        let project = plan.as_logical_project()?;
28        let input = project.input();
29        let join = input.as_logical_join()?;
30        let outer_output_indices = project.try_as_projection()?;
31        let inner_output_indices = join.output_indices();
32
33        // We cannot deal with repeated output indices in join
34        if has_repeated_element(&outer_output_indices) {
35            return None;
36        }
37        let output_indices: Vec<usize> = outer_output_indices
38            .into_iter()
39            .map(|i| inner_output_indices[i])
40            .collect();
41        Some(join.clone_with_output_indices(output_indices).into())
42    }
43}
44
45fn has_repeated_element(slice: &[usize]) -> bool {
46    (1..slice.len()).any(|i| slice[i..].contains(&slice[i - 1]))
47}
risingwave_frontend/optimizer/rule/project_join_merge_rule.rs

risingwave_frontend/optimizer/rule/
project_join_merge_rule.rs
