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arangodb/arangod/Aql/OptimizerRules.h

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////////////////////////////////////////////////////////////////////////////////
/// @brief rules for the query optimizer
///
/// @file arangod/Aql/OptimizerRules.h
///
/// DISCLAIMER
///
/// Copyright 2010-2014 triagens GmbH, Cologne, Germany
///
/// Licensed 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.
///
/// Copyright holder is triAGENS GmbH, Cologne, Germany
///
/// @author Max Neunhoeffer
/// @author Copyright 2014, triagens GmbH, Cologne, Germany
////////////////////////////////////////////////////////////////////////////////
#ifndef ARANGOD_AQL_OPTIMIZER_RULES_H
#define ARANGOD_AQL_OPTIMIZER_RULES 1
#include <Basics/Common.h>
#include "Aql/Optimizer.h"
namespace triagens {
namespace aql {
// -----------------------------------------------------------------------------
// --SECTION-- rules for the optimizer
// -----------------------------------------------------------------------------
////////////////////////////////////////////////////////////////////////////////
/// @brief remove redundant sorts
/// this rule modifies the plan in place:
/// - sorts that are covered by earlier sorts will be removed
////////////////////////////////////////////////////////////////////////////////
int removeRedundantSorts (Optimizer*, ExecutionPlan*, Optimizer::Rule const*);
////////////////////////////////////////////////////////////////////////////////
/// @brief remove all unnecessary filters
/// this rule modifies the plan in place:
/// - filters that are always true are removed completely
/// - filters that are always false will be replaced by a NoResults node
////////////////////////////////////////////////////////////////////////////////
int removeUnnecessaryFiltersRule (Optimizer*, ExecutionPlan*, Optimizer::Rule const*);
////////////////////////////////////////////////////////////////////////////////
/// @brief move calculations up in the plan
/// this rule modifies the plan in place
/// it aims to move up calculations as far up in the plan as possible, to
/// avoid redundant calculations in inner loops
////////////////////////////////////////////////////////////////////////////////
int moveCalculationsUpRule (Optimizer*, ExecutionPlan*, Optimizer::Rule const*);
////////////////////////////////////////////////////////////////////////////////
/// @brief move filters up in the plan
/// this rule modifies the plan in place
/// filters are moved as far up in the plan as possible to make result sets
/// as small as possible as early as possible
/// filters are not pushed beyond limits
////////////////////////////////////////////////////////////////////////////////
int moveFiltersUpRule (Optimizer*, ExecutionPlan*, Optimizer::Rule const*);
////////////////////////////////////////////////////////////////////////////////
/// @brief remove redundant CalculationNodes
////////////////////////////////////////////////////////////////////////////////
int removeRedundantCalculationsRule (Optimizer*, ExecutionPlan*, Optimizer::Rule const*);
////////////////////////////////////////////////////////////////////////////////
/// @brief remove CalculationNodes and SubqueryNodes that are never needed
////////////////////////////////////////////////////////////////////////////////
int removeUnnecessaryCalculationsRule (Optimizer*, ExecutionPlan*, Optimizer::Rule const*);
////////////////////////////////////////////////////////////////////////////////
/// @brief prefer IndexRange nodes over EnumerateCollection nodes
////////////////////////////////////////////////////////////////////////////////
int useIndexRange (Optimizer*, ExecutionPlan*, Optimizer::Rule const*);
////////////////////////////////////////////////////////////////////////////////
/// @brief try to use the index for sorting
////////////////////////////////////////////////////////////////////////////////
int useIndexForSort (Optimizer*, ExecutionPlan*, Optimizer::Rule const*);
////////////////////////////////////////////////////////////////////////////////
/// @brief interchange adjacent EnumerateCollectionNodes in all possible ways
////////////////////////////////////////////////////////////////////////////////
int interchangeAdjacentEnumerations (Optimizer*, ExecutionPlan*, Optimizer::Rule const*);
////////////////////////////////////////////////////////////////////////////////
/// @brief distribute operations in cluster
////////////////////////////////////////////////////////////////////////////////
int scatterInCluster (Optimizer*, ExecutionPlan*, Optimizer::Rule const*);
int distributeInCluster (Optimizer*, ExecutionPlan*, Optimizer::Rule const*);
int distributeFilternCalcToCluster (Optimizer*, ExecutionPlan*, Optimizer::Rule const*);
int distributeSortToCluster (Optimizer*, ExecutionPlan*, Optimizer::Rule const*);
////////////////////////////////////////////////////////////////////////////////
/// @brief try to get rid of a RemoteNode->ScatterNode combination which has
/// only a SingletonNode and possibly some CalculationNodes as dependencies
////////////////////////////////////////////////////////////////////////////////
int removeUnnecessaryRemoteScatter (Optimizer*, ExecutionPlan*, Optimizer::Rule const*);
////////////////////////////////////////////////////////////////////////////////
/// @brief recognises that a RemoveNode can be moved to the shards.
////////////////////////////////////////////////////////////////////////////////
int undistributeRemoveAfterEnumColl (Optimizer*, ExecutionPlan*, Optimizer::Rule const*);
} // namespace aql
} // namespace triagens
#endif
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