mirror of https://gitee.com/bigwinds/arangodb
146 lines
4.6 KiB
C++
146 lines
4.6 KiB
C++
////////////////////////////////////////////////////////////////////////////////
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/// DISCLAIMER
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///
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/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
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/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
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///
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/// Licensed under the Apache License, Version 2.0 (the "License");
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/// you may not use this file except in compliance with the License.
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/// You may obtain a copy of the License at
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///
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/// http://www.apache.org/licenses/LICENSE-2.0
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///
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/// Unless required by applicable law or agreed to in writing, software
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/// distributed under the License is distributed on an "AS IS" BASIS,
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/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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/// See the License for the specific language governing permissions and
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/// limitations under the License.
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///
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/// Copyright holder is ArangoDB GmbH, Cologne, Germany
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///
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/// @author Max Neunhoeffer
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////////////////////////////////////////////////////////////////////////////////
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#ifndef ARANGOD_AQL_SORT_NODE_H
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#define ARANGOD_AQL_SORT_NODE_H 1
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#include "Basics/Common.h"
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#include "Aql/Ast.h"
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#include "Aql/ExecutionNode.h"
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#include "Aql/types.h"
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#include "Aql/Variable.h"
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#include "VocBase/voc-types.h"
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#include "VocBase/vocbase.h"
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#include <velocypack/Slice.h>
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namespace arangodb {
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namespace basics {
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class StringBuffer;
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}
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namespace aql {
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class ExecutionBlock;
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class ExecutionPlan;
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class RedundantCalculationsReplacer;
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/// @brief class SortNode
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class SortNode : public ExecutionNode {
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friend class ExecutionBlock;
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friend class SortBlock;
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friend class RedundantCalculationsReplacer;
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public:
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SortNode(ExecutionPlan* plan, size_t id, SortElementVector const& elements,
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bool stable)
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: ExecutionNode(plan, id), _reinsertInCluster(true), _elements(elements), _stable(stable) {}
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SortNode(ExecutionPlan* plan, arangodb::velocypack::Slice const& base,
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SortElementVector const& elements, bool stable);
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/// @brief return the type of the node
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NodeType getType() const override final { return SORT; }
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/// @brief whether or not the sort is stable
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inline bool isStable() const { return _stable; }
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/// @brief export to VelocyPack
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void toVelocyPackHelper(arangodb::velocypack::Builder&,
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unsigned flags) const override final;
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/// @brief creates corresponding ExecutionBlock
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std::unique_ptr<ExecutionBlock> createBlock(
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ExecutionEngine& engine,
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std::unordered_map<ExecutionNode*, ExecutionBlock*> const&,
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std::unordered_set<std::string> const&
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) const override;
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/// @brief clone ExecutionNode recursively
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ExecutionNode* clone(ExecutionPlan* plan, bool withDependencies,
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bool withProperties) const override final {
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auto c = std::make_unique<SortNode>(plan, _id, _elements, _stable);
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cloneHelper(c.get(), withDependencies, withProperties);
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return c.release();
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}
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/// @brief estimateCost
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double estimateCost(size_t&) const override final;
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/// @brief getVariablesUsedHere, returning a vector
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std::vector<Variable const*> getVariablesUsedHere() const override final {
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std::vector<Variable const*> v;
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v.reserve(_elements.size());
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for (auto& p : _elements) {
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v.emplace_back(p.var);
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}
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return v;
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}
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/// @brief getVariablesUsedHere, modifying the set in-place
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void getVariablesUsedHere(
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std::unordered_set<Variable const*>& vars) const override final {
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for (auto& p : _elements) {
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vars.emplace(p.var);
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}
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}
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/// @brief get Variables Used Here including ASC/DESC
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SortElementVector const& elements() const { return _elements; }
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/// @brief returns all sort information
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SortInformation getSortInformation(ExecutionPlan*,
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arangodb::basics::StringBuffer*) const;
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std::vector<std::pair<ExecutionNode*, bool>> getCalcNodePairs();
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/// @brief simplifies the expressions of the sort node
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/// this will sort expressions if they are constant
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/// the method will return true if all sort expressions were removed after
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/// simplification, and false otherwise
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bool simplify(ExecutionPlan*);
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/// @brief removes the first count conditions from the sort condition
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/// this can be used if the first conditions of the condition are constant
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/// values (e.g. when a FILTER condition exists that guarantees this)
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void removeConditions(size_t count);
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// reinsert node when building gather node - this is used e.g for the geo-index
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bool _reinsertInCluster;
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private:
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/// @brief pairs, consisting of variable and sort direction
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/// (true = ascending | false = descending)
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SortElementVector _elements;
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/// whether or not the sort is stable
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bool _stable;
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};
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} // namespace arangodb::aql
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} // namespace arangodb
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#endif
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