risingwave_frontend/optimizer/rule/batch/
batch_push_limit_to_scan_rule.rs

1// Copyright 2023 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;
16
17use super::prelude::*;
18use crate::optimizer::plan_node::generic::PhysicalPlanRef;
19use crate::optimizer::plan_node::{BatchLimit, BatchSeqScan, PlanTreeNodeUnary};
20
21pub struct BatchPushLimitToScanRule {}
22
23impl Rule<Batch> for BatchPushLimitToScanRule {
24    fn apply(&self, plan: PlanRef) -> Option<PlanRef> {
25        let limit: &BatchLimit = plan.as_batch_limit()?;
26        let limit_input = limit.input();
27        let scan: &BatchSeqScan = limit_input.as_batch_seq_scan()?;
28        if scan.limit().is_some() {
29            return None;
30        }
31        let pushed_limit = limit.limit() + limit.offset();
32        let new_scan = BatchSeqScan::new_with_dist(
33            scan.core().clone(),
34            scan.base.distribution().clone(),
35            scan.scan_ranges().iter().cloned().collect_vec(),
36            Some(pushed_limit),
37        );
38        Some(limit.clone_with_input(new_scan.into()).into())
39    }
40}
41
42impl BatchPushLimitToScanRule {
43    pub fn create() -> BoxedRule {
44        Box::new(BatchPushLimitToScanRule {})
45    }
46}

risingwave_frontend/optimizer/rule/batch/batch_push_limit_to_scan_rule.rs

risingwave_frontend/optimizer/rule/batch/
batch_push_limit_to_scan_rule.rs