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Diffstat (limited to 'src/rocksdb/monitoring/thread_status_updater.h')
| -rw-r--r-- | src/rocksdb/monitoring/thread_status_updater.h | 223 |
1 files changed, 223 insertions, 0 deletions
diff --git a/src/rocksdb/monitoring/thread_status_updater.h b/src/rocksdb/monitoring/thread_status_updater.h new file mode 100644 index 000000000..762c73ae2 --- /dev/null +++ b/src/rocksdb/monitoring/thread_status_updater.h @@ -0,0 +1,223 @@ +// Copyright (c) 2011-present, Facebook, Inc. All rights reserved. +// 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). +// +// The implementation of ThreadStatus. +// +// Note that we make get and set access to ThreadStatusData lockless. +// As a result, ThreadStatusData as a whole is not atomic. However, +// we guarantee consistent ThreadStatusData all the time whenever +// user call GetThreadList(). This consistency guarantee is done +// by having the following constraint in the internal implementation +// of set and get order: +// +// 1. When reset any information in ThreadStatusData, always start from +// clearing up the lower-level information first. +// 2. When setting any information in ThreadStatusData, always start from +// setting the higher-level information. +// 3. When returning ThreadStatusData to the user, fields are fetched from +// higher-level to lower-level. In addition, where there's a nullptr +// in one field, then all fields that has lower-level than that field +// should be ignored. +// +// The high to low level information would be: +// thread_id > thread_type > db > cf > operation > state +// +// This means user might not always get full information, but whenever +// returned by the GetThreadList() is guaranteed to be consistent. +#pragma once +#include <atomic> +#include <list> +#include <memory> +#include <mutex> +#include <string> +#include <unordered_map> +#include <unordered_set> +#include <vector> + +#include "port/port.h" +#include "rocksdb/status.h" +#include "rocksdb/thread_status.h" +#include "util/thread_operation.h" + +namespace ROCKSDB_NAMESPACE { + +class ColumnFamilyHandle; + +// The structure that keeps constant information about a column family. +struct ConstantColumnFamilyInfo { +#ifdef ROCKSDB_USING_THREAD_STATUS + public: + ConstantColumnFamilyInfo(const void* _db_key, const std::string& _db_name, + const std::string& _cf_name) + : db_key(_db_key), db_name(_db_name), cf_name(_cf_name) {} + const void* db_key; + const std::string db_name; + const std::string cf_name; +#endif // ROCKSDB_USING_THREAD_STATUS +}; + +// the internal data-structure that is used to reflect the current +// status of a thread using a set of atomic pointers. +struct ThreadStatusData { +#ifdef ROCKSDB_USING_THREAD_STATUS + explicit ThreadStatusData() : enable_tracking(false) { + thread_id.store(0); + thread_type.store(ThreadStatus::USER); + cf_key.store(nullptr); + operation_type.store(ThreadStatus::OP_UNKNOWN); + op_start_time.store(0); + state_type.store(ThreadStatus::STATE_UNKNOWN); + } + + // A flag to indicate whether the thread tracking is enabled + // in the current thread. This value will be updated based on whether + // the associated Options::enable_thread_tracking is set to true + // in ThreadStatusUtil::SetColumnFamily(). + // + // If set to false, then SetThreadOperation and SetThreadState + // will be no-op. + bool enable_tracking; + + std::atomic<uint64_t> thread_id; + std::atomic<ThreadStatus::ThreadType> thread_type; + std::atomic<void*> cf_key; + std::atomic<ThreadStatus::OperationType> operation_type; + std::atomic<uint64_t> op_start_time; + std::atomic<ThreadStatus::OperationStage> operation_stage; + std::atomic<uint64_t> op_properties[ThreadStatus::kNumOperationProperties]; + std::atomic<ThreadStatus::StateType> state_type; +#endif // ROCKSDB_USING_THREAD_STATUS +}; + +// The class that stores and updates the status of the current thread +// using a thread-local ThreadStatusData. +// +// In most of the case, you should use ThreadStatusUtil to update +// the status of the current thread instead of using ThreadSatusUpdater +// directly. +// +// @see ThreadStatusUtil +class ThreadStatusUpdater { + public: + ThreadStatusUpdater() {} + + // Releases all ThreadStatusData of all active threads. + virtual ~ThreadStatusUpdater() {} + + // Unregister the current thread. + void UnregisterThread(); + + // Reset the status of the current thread. This includes resetting + // ColumnFamilyInfoKey, ThreadOperation, and ThreadState. + void ResetThreadStatus(); + + // Set the id of the current thread. + void SetThreadID(uint64_t thread_id); + + // Register the current thread for tracking. + void RegisterThread(ThreadStatus::ThreadType ttype, uint64_t thread_id); + + // Update the column-family info of the current thread by setting + // its thread-local pointer of ThreadStateInfo to the correct entry. + void SetColumnFamilyInfoKey(const void* cf_key); + + // returns the column family info key. + const void* GetColumnFamilyInfoKey(); + + // Update the thread operation of the current thread. + void SetThreadOperation(const ThreadStatus::OperationType type); + + // The start time of the current thread operation. It is in the format + // of micro-seconds since some fixed point in time. + void SetOperationStartTime(const uint64_t start_time); + + // Set the "i"th property of the current operation. + // + // NOTE: Our practice here is to set all the thread operation properties + // and stage before we set thread operation, and thread operation + // will be set in std::memory_order_release. This is to ensure + // whenever a thread operation is not OP_UNKNOWN, we will always + // have a consistent information on its properties. + void SetThreadOperationProperty(int i, uint64_t value); + + // Increase the "i"th property of the current operation with + // the specified delta. + void IncreaseThreadOperationProperty(int i, uint64_t delta); + + // Update the thread operation stage of the current thread. + ThreadStatus::OperationStage SetThreadOperationStage( + const ThreadStatus::OperationStage stage); + + // Clear thread operation of the current thread. + void ClearThreadOperation(); + + // Reset all thread-operation-properties to 0. + void ClearThreadOperationProperties(); + + // Update the thread state of the current thread. + void SetThreadState(const ThreadStatus::StateType type); + + // Clear the thread state of the current thread. + void ClearThreadState(); + + // Obtain the status of all active registered threads. + Status GetThreadList(std::vector<ThreadStatus>* thread_list); + + // Create an entry in the global ColumnFamilyInfo table for the + // specified column family. This function should be called only + // when the current thread does not hold db_mutex. + void NewColumnFamilyInfo(const void* db_key, const std::string& db_name, + const void* cf_key, const std::string& cf_name); + + // Erase all ConstantColumnFamilyInfo that is associated with the + // specified db instance. This function should be called only when + // the current thread does not hold db_mutex. + void EraseDatabaseInfo(const void* db_key); + + // Erase the ConstantColumnFamilyInfo that is associated with the + // specified ColumnFamilyData. This function should be called only + // when the current thread does not hold db_mutex. + void EraseColumnFamilyInfo(const void* cf_key); + + // Verifies whether the input ColumnFamilyHandles matches + // the information stored in the current cf_info_map. + void TEST_VerifyColumnFamilyInfoMap( + const std::vector<ColumnFamilyHandle*>& handles, bool check_exist); + + protected: +#ifdef ROCKSDB_USING_THREAD_STATUS + // The thread-local variable for storing thread status. + static thread_local ThreadStatusData* thread_status_data_; + + // Returns the pointer to the thread status data only when the + // thread status data is non-null and has enable_tracking == true. + ThreadStatusData* GetLocalThreadStatus(); + + // Directly returns the pointer to thread_status_data_ without + // checking whether enabling_tracking is true of not. + ThreadStatusData* Get() { return thread_status_data_; } + + // The mutex that protects cf_info_map and db_key_map. + std::mutex thread_list_mutex_; + + // The current status data of all active threads. + std::unordered_set<ThreadStatusData*> thread_data_set_; + + // A global map that keeps the column family information. It is stored + // globally instead of inside DB is to avoid the situation where DB is + // closing while GetThreadList function already get the pointer to its + // CopnstantColumnFamilyInfo. + std::unordered_map<const void*, ConstantColumnFamilyInfo> cf_info_map_; + + // A db_key to cf_key map that allows erasing elements in cf_info_map + // associated to the same db_key faster. + std::unordered_map<const void*, std::unordered_set<const void*>> db_key_map_; + +#else + static ThreadStatusData* thread_status_data_; +#endif // ROCKSDB_USING_THREAD_STATUS +}; + +} // namespace ROCKSDB_NAMESPACE |