mirror of https://gitee.com/bigwinds/arangodb
89 lines
2.7 KiB
C++
89 lines
2.7 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 Jan Steemann
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////////////////////////////////////////////////////////////////////////////////
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#ifndef ARANGOD_MMFILES_SYNCHRONIZER_THREAD_H
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#define ARANGOD_MMFILES_SYNCHRONIZER_THREAD_H 1
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#include "Basics/Common.h"
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#include "Basics/ConditionVariable.h"
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#include "Basics/Thread.h"
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#include "MMFiles/MMFilesWalLogfile.h"
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namespace arangodb {
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class MMFilesLogfileManager;
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class MMFilesSynchronizerThread final : public Thread {
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/// @brief MMFilesSynchronizerThread
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private:
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MMFilesSynchronizerThread(MMFilesSynchronizerThread const&) = delete;
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MMFilesSynchronizerThread& operator=(MMFilesSynchronizerThread const&) = delete;
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public:
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MMFilesSynchronizerThread(MMFilesLogfileManager&, uint64_t);
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~MMFilesSynchronizerThread() { shutdown(); }
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public:
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void beginShutdown() override final;
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public:
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/// @brief signal that a sync is needed
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void signalSync(bool waitForSync);
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protected:
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void run() override;
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private:
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/// @brief synchronize an unsynchronized region
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int doSync(bool&);
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/// @brief get a logfile descriptor (it caches the descriptor for performance)
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int getLogfileDescriptor(MMFilesWalLogfile::IdType);
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private:
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/// @brief the logfile manager
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MMFilesLogfileManager& _logfileManager;
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/// @brief condition variable for the thread
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basics::ConditionVariable _condition;
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/// @brief wait interval for the synchronizer thread when idle
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uint64_t const _syncInterval;
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/// @brief logfile descriptor cache
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struct {
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MMFilesWalLogfile::IdType id;
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int fd;
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} _logfileCache;
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/// @brief number of requests waiting
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/// the value stored here consists of two parts:
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/// the lower 32 bits contain the number of waiters that requested
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/// a synchronous write, the upper 32 bits contain the number of
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/// waiters that requested asynchronous writes
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std::atomic<uint64_t> _waiting;
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};
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} // namespace arangodb
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#endif
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