| /** |
| * 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 QUERY_OPTIMIZER_COST_MODEL_COST_MODEL_HPP_ |
| #define QUERY_OPTIMIZER_COST_MODEL_COST_MODEL_HPP_ |
| |
| #include <cstddef> |
| #include <exception> |
| #include <string> |
| |
| #include "query_optimizer/physical/Aggregate.hpp" |
| #include "query_optimizer/physical/Physical.hpp" |
| #include "utility/Macros.hpp" |
| |
| namespace quickstep { |
| namespace optimizer { |
| namespace cost { |
| |
| /** \addtogroup CostModel |
| * @{ |
| */ |
| |
| /** |
| * @brief Exception thrown for unsupported physical plan. |
| **/ |
| class UnsupportedPhysicalPlan : public std::exception { |
| public: |
| /** |
| * @brief Constructor. |
| * |
| * @param physical_plan The physical plan that is not supported by the cost |
| * model. |
| **/ |
| explicit UnsupportedPhysicalPlan(const physical::PhysicalPtr &physical_plan) |
| : message_("UnsupportedPhysicalPlan: \n" + physical_plan->toString()) { |
| } |
| |
| ~UnsupportedPhysicalPlan() throw() { |
| } |
| |
| virtual const char* what() const throw() { |
| return message_.c_str(); |
| } |
| |
| private: |
| std::string message_; |
| }; |
| |
| /** |
| * @brief Interface to a cost model of physical plans. |
| */ |
| class CostModel { |
| public: |
| /** |
| * @brief Destructor. |
| */ |
| virtual ~CostModel() {} |
| |
| /** |
| * @brief Estimate the cardinality of the output relation of \p physical_plan. |
| * |
| * @param physical_plan The physical plan for which the cardinality of the |
| * output relation is estimated. |
| * @return The estimated cardinality. |
| */ |
| virtual std::size_t estimateCardinality( |
| const physical::PhysicalPtr &physical_plan) = 0; |
| |
| /** |
| * @brief Estimate the number of groups of an aggregation. |
| * |
| * @param aggregate The physical plan of the aggregation. |
| * @return The estimated number of groups. |
| */ |
| virtual std::size_t estimateNumGroupsForAggregate(const physical::AggregatePtr &aggregate) { |
| return estimateCardinality(aggregate); |
| } |
| |
| protected: |
| /** |
| * @brief Constructor. |
| */ |
| CostModel() {} |
| |
| private: |
| DISALLOW_COPY_AND_ASSIGN(CostModel); |
| }; |
| |
| /** @} */ |
| |
| } // namespace cost |
| } // namespace optimizer |
| } // namespace quickstep |
| |
| #endif /* QUERY_OPTIMIZER_COST_MODEL_COST_MODEL_HPP_ */ |