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// Copyright (c) Meta Platforms, Inc. and affiliates.
//
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#pragma once
#ifndef ROCKSDB_LITE
#include "util/timer.h"
namespace ROCKSDB_NAMESPACE {
class SystemClock;
using PeriodicTaskFunc = std::function<void()>;
constexpr uint64_t kInvalidPeriodSec = 0;
// List of task types
enum class PeriodicTaskType : uint8_t {
kDumpStats = 0,
kPersistStats,
kFlushInfoLog,
kRecordSeqnoTime,
kMax,
};
// PeriodicTaskScheduler contains the periodic task scheduled from the DB
// instance. It's used to schedule/unschedule DumpStats(), PersistStats(),
// FlushInfoLog(), etc. Each type of the task can only have one instance,
// re-register the same task type would only update the repeat period.
//
// Internally, it uses a global single threaded timer object to run the periodic
// task functions. Timer thread will always be started since the info log
// flushing cannot be disabled.
class PeriodicTaskScheduler {
public:
explicit PeriodicTaskScheduler() = default;
PeriodicTaskScheduler(const PeriodicTaskScheduler&) = delete;
PeriodicTaskScheduler(PeriodicTaskScheduler&&) = delete;
PeriodicTaskScheduler& operator=(const PeriodicTaskScheduler&) = delete;
PeriodicTaskScheduler& operator=(PeriodicTaskScheduler&&) = delete;
// Register a task with its default repeat period
Status Register(PeriodicTaskType task_type, const PeriodicTaskFunc& fn);
// Register a task with specified repeat period. 0 is an invalid argument
// (kInvalidPeriodSec). To stop the task, please use Unregister() specifically
Status Register(PeriodicTaskType task_type, const PeriodicTaskFunc& fn,
uint64_t repeat_period_seconds);
// Unregister the task
Status Unregister(PeriodicTaskType task_type);
#ifndef NDEBUG
// Override the timer for the unittest
void TEST_OverrideTimer(SystemClock* clock);
// Call Timer TEST_WaitForRun() which wait until Timer starting waiting.
void TEST_WaitForRun(const std::function<void()>& callback) const {
if (timer_ != nullptr) {
timer_->TEST_WaitForRun(callback);
}
}
// Get global valid task number in the Timer
size_t TEST_GetValidTaskNum() const {
if (timer_ != nullptr) {
return timer_->TEST_GetPendingTaskNum();
}
return 0;
}
// If it has the specified task type registered
bool TEST_HasTask(PeriodicTaskType task_type) const {
auto it = tasks_map_.find(task_type);
return it != tasks_map_.end();
}
#endif // NDEBUG
private:
// default global Timer instance
static Timer* Default();
// Internal structure to store task information
struct TaskInfo {
TaskInfo(std::string _name, uint64_t _repeat_every_sec)
: name(std::move(_name)), repeat_every_sec(_repeat_every_sec) {}
std::string name;
uint64_t repeat_every_sec;
};
// Internal tasks map
std::map<PeriodicTaskType, TaskInfo> tasks_map_;
// Global timer pointer, which doesn't support synchronous add/cancel tasks
// so having a global `timer_mutex` for add/cancel task.
Timer* timer_ = Default();
// Global task id, protected by the global `timer_mutex`
inline static uint64_t id_;
static constexpr uint64_t kMicrosInSecond = 1000U * 1000U;
};
} // namespace ROCKSDB_NAMESPACE
#endif // ROCKSDB_LITE
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