mirror of https://github.com/facebook/rocksdb.git
90 lines
3.0 KiB
C++
90 lines
3.0 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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#pragma once
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#include <map>
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#include <queue>
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#include <string>
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#include <thread>
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#include "port/port.h"
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#include "rocksdb/status.h"
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namespace rocksdb {
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class Env;
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class Logger;
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class SstFileManagerImpl;
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// DeleteScheduler allows the DB to enforce a rate limit on file deletion,
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// Instead of deleteing files immediately, files are moved to trash_dir
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// and deleted in a background thread that apply sleep penlty between deletes
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// if they are happening in a rate faster than rate_bytes_per_sec,
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//
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// Rate limiting can be turned off by setting rate_bytes_per_sec = 0, In this
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// case DeleteScheduler will delete files immediately.
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class DeleteScheduler {
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public:
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DeleteScheduler(Env* env, const std::string& trash_dir,
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int64_t rate_bytes_per_sec, Logger* info_log,
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SstFileManagerImpl* sst_file_manager);
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~DeleteScheduler();
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// Return delete rate limit in bytes per second
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int64_t GetRateBytesPerSecond() { return rate_bytes_per_sec_; }
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// Move file to trash directory and schedule it's deletion
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Status DeleteFile(const std::string& fname);
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// Wait for all files being deleteing in the background to finish or for
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// destructor to be called.
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void WaitForEmptyTrash();
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// Return a map containing errors that happened in BackgroundEmptyTrash
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// file_path => error status
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std::map<std::string, Status> GetBackgroundErrors();
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private:
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Status MoveToTrash(const std::string& file_path, std::string* path_in_trash);
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Status DeleteTrashFile(const std::string& path_in_trash,
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uint64_t* deleted_bytes);
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void BackgroundEmptyTrash();
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Env* env_;
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// Path to the trash directory
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std::string trash_dir_;
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// Maximum number of bytes that should be deleted per second
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int64_t rate_bytes_per_sec_;
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// Mutex to protect queue_, pending_files_, bg_errors_, closing_
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port::Mutex mu_;
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// Queue of files in trash that need to be deleted
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std::queue<std::string> queue_;
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// Number of files in trash that are waiting to be deleted
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int32_t pending_files_;
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// Errors that happened in BackgroundEmptyTrash (file_path => error)
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std::map<std::string, Status> bg_errors_;
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// Set to true in ~DeleteScheduler() to force BackgroundEmptyTrash to stop
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bool closing_;
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// Condition variable signaled in these conditions
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// - pending_files_ value change from 0 => 1
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// - pending_files_ value change from 1 => 0
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// - closing_ value is set to true
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port::CondVar cv_;
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// Background thread running BackgroundEmptyTrash
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std::unique_ptr<std::thread> bg_thread_;
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// Mutex to protect threads from file name conflicts
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port::Mutex file_move_mu_;
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Logger* info_log_;
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SstFileManagerImpl* sst_file_manager_;
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static const uint64_t kMicrosInSecond = 1000 * 1000LL;
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};
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} // namespace rocksdb
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