risingwave_frontend/optimizer/rule/
union_to_distinct_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::generic::{Agg, GenericPlanRef};
18use crate::optimizer::plan_node::{LogicalUnion, PlanTreeNode};
19
20/// Convert union to distinct + union all
21pub struct UnionToDistinctRule {}
22impl Rule for UnionToDistinctRule {
23    fn apply(&self, plan: PlanRef) -> Option<PlanRef> {
24        let union: &LogicalUnion = plan.as_logical_union()?;
25        if !union.all() {
26            let union_all = LogicalUnion::create(true, union.inputs().into_iter().collect());
27            let distinct = Agg::new(vec![], (0..union.base.schema().len()).collect(), union_all)
28                .with_enable_two_phase(false);
29            Some(distinct.into())
30        } else {
31            None
32        }
33    }
34}
35
36impl UnionToDistinctRule {
37    pub fn create() -> BoxedRule {
38        Box::new(UnionToDistinctRule {})
39    }
40}

risingwave_frontend/optimizer/rule/union_to_distinct_rule.rs

risingwave_frontend/optimizer/rule/
union_to_distinct_rule.rs