risingwave_frontend/optimizer/rule/
table_function_to_postgres_query_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 itertools::Itertools;
16use risingwave_common::catalog::{Field, Schema};
17use risingwave_common::types::{DataType, ScalarImpl};
18
19use super::{BoxedRule, Rule};
20use crate::expr::{Expr, TableFunctionType};
21use crate::optimizer::PlanRef;
22use crate::optimizer::plan_node::generic::GenericPlanRef;
23use crate::optimizer::plan_node::{LogicalPostgresQuery, LogicalTableFunction};
24
25/// Transform a special `TableFunction` (with `POSTGRES_QUERY` table function type) into a `LogicalPostgresQuery`
26pub struct TableFunctionToPostgresQueryRule {}
27impl Rule for TableFunctionToPostgresQueryRule {
28    fn apply(&self, plan: PlanRef) -> Option<PlanRef> {
29        let logical_table_function: &LogicalTableFunction = plan.as_logical_table_function()?;
30        if logical_table_function.table_function.function_type != TableFunctionType::PostgresQuery {
31            return None;
32        }
33        assert!(!logical_table_function.with_ordinality);
34        let table_function_return_type = logical_table_function.table_function().return_type();
35
36        if let DataType::Struct(st) = table_function_return_type.clone() {
37            let fields = st
38                .iter()
39                .map(|(name, data_type)| Field::with_name(data_type.clone(), name.to_owned()))
40                .collect_vec();
41
42            let schema = Schema::new(fields);
43
44            assert_eq!(logical_table_function.table_function().args.len(), 6);
45            let mut eval_args = vec![];
46            for arg in &logical_table_function.table_function().args {
47                assert_eq!(arg.return_type(), DataType::Varchar);
48                let value = arg.try_fold_const().unwrap().unwrap();
49                match value {
50                    Some(ScalarImpl::Utf8(s)) => {
51                        eval_args.push(s.to_string());
52                    }
53                    _ => {
54                        unreachable!("must be a varchar")
55                    }
56                }
57            }
58            let hostname = eval_args[0].clone();
59            let port = eval_args[1].clone();
60            let username = eval_args[2].clone();
61            let password = eval_args[3].clone();
62            let database = eval_args[4].clone();
63            let query = eval_args[5].clone();
64
65            Some(
66                LogicalPostgresQuery::new(
67                    logical_table_function.ctx(),
68                    schema,
69                    hostname,
70                    port,
71                    username,
72                    password,
73                    database,
74                    query,
75                )
76                .into(),
77            )
78        } else {
79            unreachable!("TableFunction return type should be struct")
80        }
81    }
82}
83
84impl TableFunctionToPostgresQueryRule {
85    pub fn create() -> BoxedRule {
86        Box::new(TableFunctionToPostgresQueryRule {})
87    }
88}
risingwave_frontend/optimizer/rule/table_function_to_postgres_query_rule.rs

risingwave_frontend/optimizer/rule/
table_function_to_postgres_query_rule.rs
