mirror of https://github.com/facebook/rocksdb.git
79 lines
2.7 KiB
C++
79 lines
2.7 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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#pragma once
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#ifndef ROCKSDB_LITE
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#include "db/db_impl/db_impl.h"
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#include "util/timer.h"
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namespace ROCKSDB_NAMESPACE {
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class SystemClock;
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// PeriodicWorkScheduler is a singleton object, which is scheduling/running
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// DumpStats(), PersistStats(), and FlushInfoLog() for all DB instances. All DB
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// instances use the same object from `Default()`.
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//
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// Internally, it uses a single threaded timer object to run the periodic work
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// functions. Timer thread will always be started since the info log flushing
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// cannot be disabled.
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class PeriodicWorkScheduler {
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public:
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static PeriodicWorkScheduler* Default();
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PeriodicWorkScheduler() = delete;
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PeriodicWorkScheduler(const PeriodicWorkScheduler&) = delete;
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PeriodicWorkScheduler(PeriodicWorkScheduler&&) = delete;
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PeriodicWorkScheduler& operator=(const PeriodicWorkScheduler&) = delete;
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PeriodicWorkScheduler& operator=(PeriodicWorkScheduler&&) = delete;
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void Register(DBImpl* dbi, unsigned int stats_dump_period_sec,
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unsigned int stats_persist_period_sec);
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void Unregister(DBImpl* dbi);
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// Periodically flush info log out of application buffer at a low frequency.
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// This improves debuggability in case of RocksDB hanging since it ensures the
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// log messages leading up to the hang will eventually become visible in the
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// log.
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static const uint64_t kDefaultFlushInfoLogPeriodSec = 10;
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protected:
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std::unique_ptr<Timer> timer;
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// `timer_mu_` serves two purposes currently:
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// (1) to ensure calls to `Start()` and `Shutdown()` are serialized, as
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// they are currently not implemented in a thread-safe way; and
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// (2) to ensure the `Timer::Add()`s and `Timer::Start()` run atomically, and
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// the `Timer::Cancel()`s and `Timer::Shutdown()` run atomically.
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port::Mutex timer_mu_;
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explicit PeriodicWorkScheduler(const std::shared_ptr<SystemClock>& clock);
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private:
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std::string GetTaskName(DBImpl* dbi, const std::string& func_name);
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};
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#ifndef NDEBUG
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// PeriodicWorkTestScheduler is for unittest, which can specify the SystemClock
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// It also contains functions for unittest.
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class PeriodicWorkTestScheduler : public PeriodicWorkScheduler {
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public:
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static PeriodicWorkTestScheduler* Default(
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const std::shared_ptr<SystemClock>& clock);
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void TEST_WaitForRun(std::function<void()> callback) const;
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size_t TEST_GetValidTaskNum() const;
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private:
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explicit PeriodicWorkTestScheduler(const std::shared_ptr<SystemClock>& clock);
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};
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#endif // !NDEBUG
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} // namespace ROCKSDB_NAMESPACE
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#endif // ROCKSDB_LITE
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