risingwave_frontend/optimizer/rule/stream/
separate_consecutive_join_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::prelude::*;
16use crate::optimizer::plan_node::generic::Join;
17use crate::optimizer::plan_node::{PlanTreeNodeBinary, StreamExchange, StreamHashJoin};
18
19/// Separate consecutive stream hash joins by no-shuffle exchange
20pub struct SeparateConsecutiveJoinRule {}
21
22impl Rule<Stream> for SeparateConsecutiveJoinRule {
23    fn apply(&self, plan: PlanRef) -> Option<PlanRef> {
24        let join = plan.as_stream_hash_join()?;
25        let left_input = join.left();
26        let right_input = join.right();
27
28        let new_left = if left_input.as_stream_hash_join().is_some() {
29            StreamExchange::new_no_shuffle(left_input).into()
30        } else {
31            left_input
32        };
33
34        let new_right = if right_input.as_stream_hash_join().is_some() {
35            StreamExchange::new_no_shuffle(right_input).into()
36        } else {
37            right_input
38        };
39
40        let core = Join::with_full_output_eq_predicate(
41            new_left,
42            new_right,
43            join.join_type(),
44            join.eq_join_predicate().clone(),
45        );
46        Some(StreamHashJoin::new(core).unwrap().into())
47    }
48}
49
50impl SeparateConsecutiveJoinRule {
51    pub fn create() -> BoxedRule {
52        Box::new(SeparateConsecutiveJoinRule {})
53    }
54}