datafusion 1.0.1

DataFusion is an in-memory query engine that uses Apache Arrow as the memory model
Documentation 
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// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

//! Query optimizer traits

use crate::error::Result;
use crate::logicalplan::LogicalPlan;

/// An optimizer rules performs a transformation on a logical plan to produce an optimized
/// logical plan.
pub trait OptimizerRule {
    /// Perform optimizations on the plan
    fn optimize(&mut self, plan: &LogicalPlan) -> Result<LogicalPlan>;
}