query_optimizer/rules/GenerateJoins.hpp

/**
 * 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.
 **/

#ifndef QUICKSTEP_QUERY_OPTIMIZER_RULES_GENERATE_JOINS_HPP_
#define QUICKSTEP_QUERY_OPTIMIZER_RULES_GENERATE_JOINS_HPP_

#include <map>
#include <string>
#include <vector>

#include "query_optimizer/logical/Logical.hpp"
#include "query_optimizer/rules/TopDownRule.hpp"
#include "utility/Macros.hpp"

namespace quickstep {
namespace optimizer {

/** \addtogroup OptimizerRules
 *  @{
 */

/**
 * @brief Rule that converts a MultiwayCartesianJoin to a deterministic chain of
 *        join operators. It does not do cost-based join ordering
 *        optimization TODO(quickstep-team). Hash joins are performed before
 *        nested loops join. The join ordering among hash joins and among nested
 *        loops joins follow the ordering of the predicates given by the query.
 */
class GenerateJoins : public TopDownRule<logical::Logical> {
 public:
  /**
   * @brief Constructor.
   */
  GenerateJoins() {}

  std::string getName() const override { return "GenerateJoins"; }

 protected:
  logical::LogicalPtr applyToNode(const logical::LogicalPtr &input) override;

 private:
  DISALLOW_COPY_AND_ASSIGN(GenerateJoins);
};

/** @} */

}  // namespace optimizer
}  // namespace quickstep

#endif /* QUICKSTEP_QUERY_OPTIMIZER_RULES_GENERATE_JOINS_HPP_ */