risingwave_frontend/optimizer/rule/
trivial_project_to_values_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::plan_node::generic::GenericPlanRef;
17use crate::optimizer::plan_node::{LogicalValues, PlanTreeNodeUnary};
18use crate::optimizer::plan_visitor::{LogicalCardinalityExt, SideEffectVisitor};
19use crate::optimizer::{PlanRef, PlanVisitor};
20
21pub struct TrivialProjectToValuesRule {}
22impl Rule for TrivialProjectToValuesRule {
23    fn apply(&self, plan: PlanRef) -> Option<PlanRef> {
24        let project = plan.as_logical_project()?;
25
26        if !project.exprs().iter().all(|e| e.is_const()) {
27            return None;
28        }
29        if SideEffectVisitor.visit(project.input()) {
30            return None;
31        }
32
33        let row_count = project.input().row_count()?;
34        let values = LogicalValues::new(
35            vec![project.exprs().clone(); row_count],
36            project.schema().clone(),
37            project.ctx(),
38        );
39        Some(values.into())
40    }
41}
42
43impl TrivialProjectToValuesRule {
44    pub fn create() -> BoxedRule {
45        Box::new(TrivialProjectToValuesRule {})
46    }
47}