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arangodb/arangod/Aql/PlanCache.h

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////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 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 ArangoDB GmbH, Cologne, Germany
///
/// @author Jan Steemann
////////////////////////////////////////////////////////////////////////////////
#ifndef ARANGOD_AQL_PLAN_CACHE_H
#define ARANGOD_AQL_PLAN_CACHE_H 1
#include "Basics/Common.h"
#include "Basics/ReadWriteLock.h"
struct TRI_vocbase_t;
namespace arangodb {
namespace velocypack {
class Builder;
}
namespace aql {
class ExecutionPlan;
class QueryString;
class VariableGenerator;
struct PlanCacheEntry {
PlanCacheEntry(std::string&& queryString,
std::shared_ptr<arangodb::velocypack::Builder>&& builder)
: queryString(std::move(queryString)), builder(std::move(builder)) {}
std::string queryString;
std::shared_ptr<arangodb::velocypack::Builder> builder;
};
class PlanCache {
public:
PlanCache(PlanCache const&) = delete;
PlanCache& operator=(PlanCache const&) = delete;
/// @brief create cache
PlanCache();
/// @brief destroy the cache
~PlanCache();
public:
/// @brief lookup a plan in the cache
std::shared_ptr<PlanCacheEntry> lookup(TRI_vocbase_t*, uint64_t, QueryString const&);
/// @brief store a plan in the cache
void store(TRI_vocbase_t*, uint64_t, QueryString const&, ExecutionPlan const*);
/// @brief invalidate all plans for a particular database
void invalidate(TRI_vocbase_t*);
/// @brief get the pointer to the global plan cache
static PlanCache* instance();
private:
/// @brief read-write lock for the cache
arangodb::basics::ReadWriteLock _lock;
/// @brief cached query plans, organized per database
std::unordered_map<TRI_vocbase_t*, std::unordered_map<uint64_t, std::shared_ptr<PlanCacheEntry>>> _plans;
};
}
}
#endif