| /** |
| * 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_STAR_SCHEMA_SIMPLE_COST_MODEL_HPP_ |
| #define QUERY_OPTIMIZER_COST_MODEL_STAR_SCHEMA_SIMPLE_COST_MODEL_HPP_ |
| |
| #include <cstddef> |
| #include <vector> |
| |
| #include "query_optimizer/cost_model/CostModel.hpp" |
| #include "query_optimizer/expressions/ExprId.hpp" |
| #include "query_optimizer/expressions/Predicate.hpp" |
| #include "query_optimizer/physical/Aggregate.hpp" |
| #include "query_optimizer/physical/NestedLoopsJoin.hpp" |
| #include "query_optimizer/physical/HashJoin.hpp" |
| #include "query_optimizer/physical/Physical.hpp" |
| #include "query_optimizer/physical/Selection.hpp" |
| #include "query_optimizer/physical/Sort.hpp" |
| #include "query_optimizer/physical/TableGenerator.hpp" |
| #include "query_optimizer/physical/TableReference.hpp" |
| #include "query_optimizer/physical/TopLevelPlan.hpp" |
| #include "query_optimizer/physical/WindowAggregate.hpp" |
| #include "utility/Macros.hpp" |
| |
| namespace quickstep { |
| namespace optimizer { |
| namespace cost { |
| |
| /** \addtogroup CostModel |
| * @{ |
| */ |
| |
| /** |
| * @brief A simple cost model for hash join planning. |
| */ |
| class StarSchemaSimpleCostModel : public CostModel { |
| public: |
| /** |
| * @brief Constructor. |
| */ |
| explicit StarSchemaSimpleCostModel(const std::vector<physical::PhysicalPtr> &shared_subplans) |
| : shared_subplans_(shared_subplans) {} |
| |
| /** |
| * @brief Estimate the cardinality of a physical plan. |
| * |
| * @param physical_plan The physical plan. |
| * @return The estimated cardinality. |
| */ |
| std::size_t estimateCardinality( |
| const physical::PhysicalPtr &physical_plan) override; |
| |
| /** |
| * @brief Estimate the number of groups in an aggregation. |
| * |
| * @param aggregate The physical plan of the aggregation. |
| * @return The estimated number of groups. |
| */ |
| std::size_t estimateNumGroupsForAggregate( |
| const physical::AggregatePtr &aggregate) override; |
| |
| /** |
| * @brief Estimate the number of distinct values of an attribute in a relation. |
| * |
| * @param attribute_id The expression id of the target attribute. |
| * @param physical_plan The physical plan of the attribute's relation. |
| * @return The estimated number of distinct values for the attribute. |
| */ |
| std::size_t estimateNumDistinctValues(const expressions::ExprId attribute_id, |
| const physical::PhysicalPtr &physical_plan); |
| |
| /** |
| * @brief Estimate the "selectivity" of a physical plan under the assumption |
| * that it acts as a filtered dimension table in a hash join. |
| * |
| * @param phyiscal_plan The physical plan. |
| * @return The estimated selectivity. |
| */ |
| double estimateSelectivity(const physical::PhysicalPtr &physical_plan); |
| |
| /** |
| * @brief Estimate the filter predicate's selectivity if it is present in |
| * the input plan's root node. |
| * |
| * @param physical_plan The input physical plan. |
| * @return The estimated selectivity of the filter predicate if physical_plan |
| * has such a filter predicate; 1.0 otherwise. |
| */ |
| double estimateSelectivityForFilterPredicate( |
| const physical::PhysicalPtr &physical_plan); |
| |
| private: |
| std::size_t estimateCardinalityForAggregate( |
| const physical::AggregatePtr &physical_plan); |
| |
| std::size_t estimateCardinalityForHashJoin( |
| const physical::HashJoinPtr &physical_plan); |
| |
| std::size_t estimateCardinalityForNestedLoopsJoin( |
| const physical::NestedLoopsJoinPtr &physical_plan); |
| |
| std::size_t estimateCardinalityForSelection( |
| const physical::SelectionPtr &physical_plan); |
| |
| std::size_t estimateCardinalityForSort( |
| const physical::SortPtr &physical_plan); |
| |
| std::size_t estimateCardinalityForTableGenerator( |
| const physical::TableGeneratorPtr &physical_plan); |
| |
| std::size_t estimateCardinalityForTableReference( |
| const physical::TableReferencePtr &physical_plan); |
| |
| std::size_t estimateCardinalityForTopLevelPlan( |
| const physical::TopLevelPlanPtr &physical_plan); |
| |
| std::size_t estimateCardinalityForWindowAggregate( |
| const physical::WindowAggregatePtr &physical_plan); |
| |
| double estimateSelectivityForPredicate( |
| const expressions::PredicatePtr &filter_predicate, |
| const physical::PhysicalPtr &physical_plan); |
| |
| const std::vector<physical::PhysicalPtr> &shared_subplans_; |
| |
| // Get the number of distinct values of an attribute in the table reference. |
| // If the stat is not avaiable, simply returns the table's cardinality. |
| std::size_t getNumDistinctValues(const expressions::ExprId attribute_id, |
| const physical::TableReferencePtr &table_reference); |
| |
| |
| DISALLOW_COPY_AND_ASSIGN(StarSchemaSimpleCostModel); |
| }; |
| |
| /** @} */ |
| |
| } // namespace cost |
| } // namespace optimizer |
| } // namespace quickstep |
| |
| #endif /* QUERY_OPTIMIZER_COST_MODEL_STAR_SCHEMA_SIMPLE_COST_MODEL_HPP_ */ |