risingwave_frontend/optimizer/rule/
expand_to_project_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};
17use crate::expr::{ExprImpl, InputRef};
18use crate::optimizer::plan_node::generic::GenericPlanRef;
19
20pub struct ExpandToProjectRule {}
21
22impl ExpandToProjectRule {
23    pub fn create() -> BoxedRule {
24        Box::new(Self {})
25    }
26}
27impl Rule for ExpandToProjectRule {
28    fn apply(&self, plan: PlanRef) -> Option<PlanRef> {
29        let expand: &LogicalExpand = plan.as_logical_expand()?;
30        let (input, column_subsets) = expand.clone().decompose();
31        assert!(!column_subsets.is_empty());
32        if column_subsets.len() > 1 {
33            return None;
34        }
35        assert!(column_subsets.len() == 1);
36        let column_subset = column_subsets.first().unwrap();
37
38        // if `column_subsets` len equals 1, convert it into a project
39        let mut exprs = Vec::with_capacity(expand.base.schema().len());
40        // Add original input column first
41        for i in 0..input.schema().len() {
42            exprs.push(ExprImpl::InputRef(
43                InputRef::new(i, input.schema()[i].data_type()).into(),
44            ));
45        }
46        // Add column sets
47        for i in 0..input.schema().len() {
48            let expr = if column_subset.contains(&i) {
49                ExprImpl::InputRef(InputRef::new(i, input.schema()[i].data_type()).into())
50            } else {
51                ExprImpl::literal_null(input.schema()[i].data_type())
52            };
53            exprs.push(expr);
54        }
55        // Add flag
56        exprs.push(ExprImpl::literal_bigint(0));
57
58        Some(LogicalProject::create(input, exprs))
59    }
60}
risingwave_frontend/optimizer/rule/expand_to_project_rule.rs

risingwave_frontend/optimizer/rule/
expand_to_project_rule.rs
