risingwave_frontend/optimizer/rule/
union_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::{BoxedRule, Rule};
16use crate::optimizer::PlanRef;
17use crate::optimizer::plan_node::{LogicalUnion, PlanTreeNode};
18
19pub struct UnionMergeRule {}
20impl Rule for UnionMergeRule {
21    fn apply(&self, plan: PlanRef) -> Option<PlanRef> {
22        let top_union: &LogicalUnion = plan.as_logical_union()?;
23        let top_all = top_union.all();
24        let mut new_inputs = vec![];
25        let mut has_merge = false;
26        for input in top_union.inputs() {
27            if let Some(bottom_union) = input.as_logical_union()
28                && bottom_union.all() == top_all
29            {
30                new_inputs.extend(bottom_union.inputs());
31                has_merge = true;
32            } else {
33                new_inputs.push(input);
34            }
35        }
36
37        if has_merge {
38            Some(top_union.clone_with_inputs(&new_inputs))
39        } else {
40            None
41        }
42    }
43}
44
45impl UnionMergeRule {
46    pub fn create() -> BoxedRule {
47        Box::new(UnionMergeRule {})
48    }
49}
risingwave_frontend/optimizer/rule/union_merge_rule.rs

risingwave_frontend/optimizer/rule/
union_merge_rule.rs
