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rocksdb/utilities/backupable/backupable_db.cc
sdong 6e9fbeb27c Move rate_limiter, write buffering, most perf context instrumentation and most random kill out of Env 
Summary: We want to keep Env a think layer for better portability. Less platform dependent codes should be moved out of Env. In this patch, I create a wrapper of file readers and writers, and put rate limiting, write buffering, as well as most perf context instrumentation and random kill out of Env. It will make it easier to maintain multiple Env in the future.

Test Plan: Run all existing unit tests.

Reviewers: anthony, kradhakrishnan, IslamAbdelRahman, yhchiang, igor

Reviewed By: igor

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D42321
2015-07-17 16:58:18 -07:00

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// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef ROCKSDB_LITE
#include "rocksdb/utilities/backupable_db.h"
#include "db/filename.h"
#include "util/channel.h"
#include "util/coding.h"
#include "util/crc32c.h"
#include "util/file_reader_writer.h"
#include "util/logging.h"
#include "util/string_util.h"
#include "rocksdb/transaction_log.h"
#ifndef __STDC_FORMAT_MACROS
#define __STDC_FORMAT_MACROS
#endif
#include <inttypes.h>
#include <stdlib.h>
#include <algorithm>
#include <vector>
#include <map>
#include <sstream>
#include <string>
#include <limits>
#include <atomic>
#include <future>
#include <thread>
#include <unordered_map>
#include <unordered_set>
#include "port/port.h"
namespace rocksdb {
class BackupRateLimiter {
public:
BackupRateLimiter(Env* env, uint64_t max_bytes_per_second,
uint64_t bytes_per_check)
: env_(env),
max_bytes_per_second_(max_bytes_per_second),
bytes_per_check_(bytes_per_check),
micros_start_time_(env->NowMicros()),
bytes_since_start_(0) {}
void ReportAndWait(uint64_t bytes_since_last_call) {
bytes_since_start_ += bytes_since_last_call;
if (bytes_since_start_ < bytes_per_check_) {
// not enough bytes to be rate-limited
return;
}
uint64_t now = env_->NowMicros();
uint64_t interval = now - micros_start_time_;
uint64_t should_take_micros =
(bytes_since_start_ * kMicrosInSecond) / max_bytes_per_second_;
if (should_take_micros > interval) {
env_->SleepForMicroseconds(
static_cast<int>(should_take_micros - interval));
now = env_->NowMicros();
}
// reset interval
micros_start_time_ = now;
bytes_since_start_ = 0;
}
private:
Env* env_;
uint64_t max_bytes_per_second_;
uint64_t bytes_per_check_;
uint64_t micros_start_time_;
uint64_t bytes_since_start_;
static const uint64_t kMicrosInSecond = 1000 * 1000LL;
};
void BackupStatistics::IncrementNumberSuccessBackup() {
number_success_backup++;
}
void BackupStatistics::IncrementNumberFailBackup() {
number_fail_backup++;
}
uint32_t BackupStatistics::GetNumberSuccessBackup() const {
return number_success_backup;
}
uint32_t BackupStatistics::GetNumberFailBackup() const {
return number_fail_backup;
}
std::string BackupStatistics::ToString() const {
char result[50];
snprintf(result, sizeof(result), "# success backup: %u, # fail backup: %u",
GetNumberSuccessBackup(), GetNumberFailBackup());
return result;
}
void BackupableDBOptions::Dump(Logger* logger) const {
Log(logger, " Options.backup_dir: %s", backup_dir.c_str());
Log(logger, " Options.backup_env: %p", backup_env);
Log(logger, " Options.share_table_files: %d",
static_cast<int>(share_table_files));
Log(logger, " Options.info_log: %p", info_log);
Log(logger, " Options.sync: %d", static_cast<int>(sync));
Log(logger, " Options.destroy_old_data: %d",
static_cast<int>(destroy_old_data));
Log(logger, " Options.backup_log_files: %d",
static_cast<int>(backup_log_files));
Log(logger, " Options.backup_rate_limit: %" PRIu64, backup_rate_limit);
Log(logger, " Options.restore_rate_limit: %" PRIu64,
restore_rate_limit);
Log(logger, "Options.max_background_operations: %d",
max_background_operations);
}
// -------- BackupEngineImpl class ---------
class BackupEngineImpl : public BackupEngine {
public:
BackupEngineImpl(Env* db_env, const BackupableDBOptions& options,
bool read_only = false);
~BackupEngineImpl();
Status CreateNewBackup(DB* db, bool flush_before_backup = false) override;
Status PurgeOldBackups(uint32_t num_backups_to_keep) override;
Status DeleteBackup(BackupID backup_id) override;
void StopBackup() override {
stop_backup_.store(true, std::memory_order_release);
}
Status GarbageCollect() override;
void GetBackupInfo(std::vector<BackupInfo>* backup_info) override;
void GetCorruptedBackups(std::vector<BackupID>* corrupt_backup_ids) override;
Status RestoreDBFromBackup(
BackupID backup_id, const std::string& db_dir, const std::string& wal_dir,
const RestoreOptions& restore_options = RestoreOptions()) override;
Status RestoreDBFromLatestBackup(
const std::string& db_dir, const std::string& wal_dir,
const RestoreOptions& restore_options = RestoreOptions()) override {
return RestoreDBFromBackup(latest_backup_id_, db_dir, wal_dir,
restore_options);
}
Status Initialize();
private:
void DeleteChildren(const std::string& dir, uint32_t file_type_filter = 0);
struct FileInfo {
FileInfo(const std::string& fname, uint64_t sz, uint32_t checksum)
: refs(0), filename(fname), size(sz), checksum_value(checksum) {}
FileInfo(const FileInfo&) = delete;
FileInfo& operator=(const FileInfo&) = delete;
int refs;
const std::string filename;
const uint64_t size;
const uint32_t checksum_value;
};
class BackupMeta {
public:
BackupMeta(const std::string& meta_filename,
std::unordered_map<std::string, std::shared_ptr<FileInfo>>* file_infos,
Env* env)
: timestamp_(0), size_(0), meta_filename_(meta_filename),
file_infos_(file_infos), env_(env) {}
BackupMeta(const BackupMeta&) = delete;
BackupMeta& operator=(const BackupMeta&) = delete;
~BackupMeta() {}
void RecordTimestamp() {
env_->GetCurrentTime(&timestamp_);
}
int64_t GetTimestamp() const {
return timestamp_;
}
uint64_t GetSize() const {
return size_;
}
uint32_t GetNumberFiles() { return static_cast<uint32_t>(files_.size()); }
void SetSequenceNumber(uint64_t sequence_number) {
sequence_number_ = sequence_number;
}
uint64_t GetSequenceNumber() {
return sequence_number_;
}
Status AddFile(std::shared_ptr<FileInfo> file_info);
Status Delete(bool delete_meta = true);
bool Empty() {
return files_.empty();
}
std::shared_ptr<FileInfo> GetFile(const std::string& filename) const {
auto it = file_infos_->find(filename);
if (it == file_infos_->end())
return nullptr;
return it->second;
}
const std::vector<std::shared_ptr<FileInfo>>& GetFiles() {
return files_;
}
Status LoadFromFile(const std::string& backup_dir);
Status StoreToFile(bool sync);
std::string GetInfoString() {
std::ostringstream ss;
ss << "Timestamp: " << timestamp_ << std::endl;
char human_size[16];
AppendHumanBytes(size_, human_size, sizeof(human_size));
ss << "Size: " << human_size << std::endl;
ss << "Files:" << std::endl;
for (const auto& file : files_) {
AppendHumanBytes(file->size, human_size, sizeof(human_size));
ss << file->filename << ", size " << human_size << ", refs "
<< file->refs << std::endl;
}
return ss.str();
}
private:
int64_t timestamp_;
// sequence number is only approximate, should not be used
// by clients
uint64_t sequence_number_;
uint64_t size_;
std::string const meta_filename_;
// files with relative paths (without "/" prefix!!)
std::vector<std::shared_ptr<FileInfo>> files_;
std::unordered_map<std::string, std::shared_ptr<FileInfo>>* file_infos_;
Env* env_;
static const size_t max_backup_meta_file_size_ = 10 * 1024 * 1024; // 10MB
}; // BackupMeta
inline std::string GetAbsolutePath(
const std::string &relative_path = "") const {
assert(relative_path.size() == 0 || relative_path[0] != '/');
return options_.backup_dir + "/" + relative_path;
}
inline std::string GetPrivateDirRel() const {
return "private";
}
inline std::string GetSharedChecksumDirRel() const {
return "shared_checksum";
}
inline std::string GetPrivateFileRel(BackupID backup_id,
bool tmp = false,
const std::string& file = "") const {
assert(file.size() == 0 || file[0] != '/');
return GetPrivateDirRel() + "/" + rocksdb::ToString(backup_id) +
(tmp ? ".tmp" : "") + "/" + file;
}
inline std::string GetSharedFileRel(const std::string& file = "",
bool tmp = false) const {
assert(file.size() == 0 || file[0] != '/');
return "shared/" + file + (tmp ? ".tmp" : "");
}
inline std::string GetSharedFileWithChecksumRel(const std::string& file = "",
bool tmp = false) const {
assert(file.size() == 0 || file[0] != '/');
return GetSharedChecksumDirRel() + "/" + file + (tmp ? ".tmp" : "");
}
inline std::string GetSharedFileWithChecksum(const std::string& file,
const uint32_t checksum_value,
const uint64_t file_size) const {
assert(file.size() == 0 || file[0] != '/');
std::string file_copy = file;
return file_copy.insert(file_copy.find_last_of('.'),
"_" + rocksdb::ToString(checksum_value) + "_" +
rocksdb::ToString(file_size));
}
inline std::string GetFileFromChecksumFile(const std::string& file) const {
assert(file.size() == 0 || file[0] != '/');
std::string file_copy = file;
size_t first_underscore = file_copy.find_first_of('_');
return file_copy.erase(first_underscore,
file_copy.find_last_of('.') - first_underscore);
}
inline std::string GetLatestBackupFile(bool tmp = false) const {
return GetAbsolutePath(std::string("LATEST_BACKUP") + (tmp ? ".tmp" : ""));
}
inline std::string GetBackupMetaDir() const {
return GetAbsolutePath("meta");
}
inline std::string GetBackupMetaFile(BackupID backup_id) const {
return GetBackupMetaDir() + "/" + rocksdb::ToString(backup_id);
}
Status GetLatestBackupFileContents(uint32_t* latest_backup);
Status PutLatestBackupFileContents(uint32_t latest_backup);
// if size_limit == 0, there is no size limit, copy everything
Status CopyFile(const std::string& src,
const std::string& dst,
Env* src_env,
Env* dst_env,
bool sync,
BackupRateLimiter* rate_limiter,
uint64_t* size = nullptr,
uint32_t* checksum_value = nullptr,
uint64_t size_limit = 0);
Status CalculateChecksum(const std::string& src,
Env* src_env,
uint64_t size_limit,
uint32_t* checksum_value);
struct CopyResult {
uint64_t size;
uint32_t checksum_value;
Status status;
};
struct CopyWorkItem {
std::string src_path;
std::string dst_path;
Env* src_env;
Env* dst_env;
bool sync;
BackupRateLimiter* rate_limiter;
uint64_t size_limit;
std::promise<CopyResult> result;
CopyWorkItem() {}
CopyWorkItem(const CopyWorkItem&) = delete;
CopyWorkItem& operator=(const CopyWorkItem&) = delete;
CopyWorkItem(CopyWorkItem&& o) { *this = std::move(o); }
CopyWorkItem& operator=(CopyWorkItem&& o) {
src_path = std::move(o.src_path);
dst_path = std::move(o.dst_path);
src_env = o.src_env;
dst_env = o.dst_env;
sync = o.sync;
rate_limiter = o.rate_limiter;
size_limit = o.size_limit;
result = std::move(o.result);
return *this;
}
CopyWorkItem(std::string _src_path,
std::string _dst_path,
Env* _src_env,
Env* _dst_env,
bool _sync,
BackupRateLimiter* _rate_limiter,
uint64_t _size_limit)
: src_path(std::move(_src_path)),
dst_path(std::move(_dst_path)),
src_env(_src_env),
dst_env(_dst_env),
sync(_sync),
rate_limiter(_rate_limiter),
size_limit(_size_limit) {}
};
struct BackupAfterCopyWorkItem {
std::future<CopyResult> result;
bool shared;
bool needed_to_copy;
Env* backup_env;
std::string dst_path_tmp;
std::string dst_path;
std::string dst_relative;
BackupAfterCopyWorkItem() {}
BackupAfterCopyWorkItem(BackupAfterCopyWorkItem&& o) {
*this = std::move(o);
}
BackupAfterCopyWorkItem& operator=(BackupAfterCopyWorkItem&& o) {
result = std::move(o.result);
shared = o.shared;
needed_to_copy = o.needed_to_copy;
backup_env = o.backup_env;
dst_path_tmp = std::move(o.dst_path_tmp);
dst_path = std::move(o.dst_path);
dst_relative = std::move(o.dst_relative);
return *this;
}
BackupAfterCopyWorkItem(std::future<CopyResult>&& _result, bool _shared,
bool _needed_to_copy, Env* _backup_env,
std::string _dst_path_tmp, std::string _dst_path,
std::string _dst_relative)
: result(std::move(_result)),
shared(_shared),
needed_to_copy(_needed_to_copy),
backup_env(_backup_env),
dst_path_tmp(std::move(_dst_path_tmp)),
dst_path(std::move(_dst_path)),
dst_relative(std::move(_dst_relative)) {}
};
struct RestoreAfterCopyWorkItem {
std::future<CopyResult> result;
uint32_t checksum_value;
RestoreAfterCopyWorkItem() {}
RestoreAfterCopyWorkItem(std::future<CopyResult>&& _result,
uint32_t _checksum_value)
: result(std::move(_result)), checksum_value(_checksum_value) {}
RestoreAfterCopyWorkItem(RestoreAfterCopyWorkItem&& o) {
*this = std::move(o);
}
RestoreAfterCopyWorkItem& operator=(RestoreAfterCopyWorkItem&& o) {
result = std::move(o.result);
checksum_value = o.checksum_value;
return *this;
}
};
bool initialized_;
channel<CopyWorkItem> files_to_copy_;
std::vector<std::thread> threads_;
Status AddBackupFileWorkItem(
std::unordered_set<std::string>& live_dst_paths,
std::vector<BackupAfterCopyWorkItem>& backup_items_to_finish,
BackupID backup_id,
bool shared,
const std::string& src_dir,
const std::string& src_fname, // starts with "/"
BackupRateLimiter* rate_limiter,
uint64_t size_limit = 0,
bool shared_checksum = false);
// backup state data
BackupID latest_backup_id_;
std::map<BackupID, unique_ptr<BackupMeta>> backups_;
std::map<BackupID,
std::pair<Status, unique_ptr<BackupMeta>>> corrupt_backups_;
std::unordered_map<std::string,
std::shared_ptr<FileInfo>> backuped_file_infos_;
std::atomic<bool> stop_backup_;
// options data
BackupableDBOptions options_;
Env* db_env_;
Env* backup_env_;
// directories
unique_ptr<Directory> backup_directory_;
unique_ptr<Directory> shared_directory_;
unique_ptr<Directory> meta_directory_;
unique_ptr<Directory> private_directory_;
static const size_t kDefaultCopyFileBufferSize = 5 * 1024 * 1024LL; // 5MB
size_t copy_file_buffer_size_;
bool read_only_;
BackupStatistics backup_statistics_;
};
Status BackupEngine::Open(Env* env, const BackupableDBOptions& options,
BackupEngine** backup_engine_ptr) {
std::unique_ptr<BackupEngineImpl> backup_engine(
new BackupEngineImpl(env, options));
auto s = backup_engine->Initialize();
if (!s.ok()) {
*backup_engine_ptr = nullptr;
return s;
}
*backup_engine_ptr = backup_engine.release();
return Status::OK();
}
BackupEngineImpl::BackupEngineImpl(Env* db_env,
const BackupableDBOptions& options,
bool read_only)
: initialized_(false),
stop_backup_(false),
options_(options),
db_env_(db_env),
backup_env_(options.backup_env != nullptr ? options.backup_env : db_env_),
copy_file_buffer_size_(kDefaultCopyFileBufferSize),
read_only_(read_only) {}
BackupEngineImpl::~BackupEngineImpl() {
files_to_copy_.sendEof();
for (auto& t : threads_) {
t.join();
}
LogFlush(options_.info_log);
}
Status BackupEngineImpl::Initialize() {
assert(!initialized_);
initialized_ = true;
if (read_only_) {
Log(options_.info_log, "Starting read_only backup engine");
}
options_.Dump(options_.info_log);
if (!read_only_) {
// gather the list of directories that we need to create
std::vector<std::pair<std::string, std::unique_ptr<Directory>*>>
directories;
directories.emplace_back(GetAbsolutePath(), &backup_directory_);
if (options_.share_table_files) {
if (options_.share_files_with_checksum) {
directories.emplace_back(
GetAbsolutePath(GetSharedFileWithChecksumRel()),
&shared_directory_);
} else {
directories.emplace_back(GetAbsolutePath(GetSharedFileRel()),
&shared_directory_);
}
}
directories.emplace_back(GetAbsolutePath(GetPrivateDirRel()),
&private_directory_);
directories.emplace_back(GetBackupMetaDir(), &meta_directory_);
// create all the dirs we need
for (const auto& d : directories) {
auto s = backup_env_->CreateDirIfMissing(d.first);
if (s.ok()) {
s = backup_env_->NewDirectory(d.first, d.second);
}
if (!s.ok()) {
return s;
}
}
}
std::vector<std::string> backup_meta_files;
{
auto s = backup_env_->GetChildren(GetBackupMetaDir(), &backup_meta_files);
if (!s.ok()) {
return s;
}
}
// create backups_ structure
for (auto& file : backup_meta_files) {
if (file == "." || file == "..") {
continue;
}
Log(options_.info_log, "Detected backup %s", file.c_str());
BackupID backup_id = 0;
sscanf(file.c_str(), "%u", &backup_id);
if (backup_id == 0 || file != rocksdb::ToString(backup_id)) {
if (!read_only_) {
// invalid file name, delete that
auto s = backup_env_->DeleteFile(GetBackupMetaDir() + "/" + file);
Log(options_.info_log, "Unrecognized meta file %s, deleting -- %s",
file.c_str(), s.ToString().c_str());
}
continue;
}
assert(backups_.find(backup_id) == backups_.end());
backups_.insert(std::move(
std::make_pair(backup_id, unique_ptr<BackupMeta>(new BackupMeta(
GetBackupMetaFile(backup_id),
&backuped_file_infos_, backup_env_)))));
}
if (options_.destroy_old_data) { // Destroy old data
assert(!read_only_);
Log(options_.info_log,
"Backup Engine started with destroy_old_data == true, deleting all "
"backups");
auto s = PurgeOldBackups(0);
if (s.ok()) {
s = GarbageCollect();
}
if (!s.ok()) {
return s;
}
// start from beginning
latest_backup_id_ = 0;
} else { // Load data from storage
// load the backups if any
for (auto& backup : backups_) {
Status s = backup.second->LoadFromFile(options_.backup_dir);
if (!s.ok()) {
Log(options_.info_log, "Backup %u corrupted -- %s", backup.first,
s.ToString().c_str());
corrupt_backups_.insert(std::make_pair(
backup.first, std::make_pair(s, std::move(backup.second))));
} else {
Log(options_.info_log, "Loading backup %" PRIu32 " OK:\n%s",
backup.first, backup.second->GetInfoString().c_str());
}
}
for (const auto& corrupt : corrupt_backups_) {
backups_.erase(backups_.find(corrupt.first));
}
Status s = GetLatestBackupFileContents(&latest_backup_id_);
// If latest backup file is corrupted or non-existent
// set latest backup as the biggest backup we have
// or 0 if we have no backups
if (!s.ok() ||
backups_.find(latest_backup_id_) == backups_.end()) {
auto itr = backups_.end();
latest_backup_id_ = (itr == backups_.begin()) ? 0 : (--itr)->first;
}
}
Log(options_.info_log, "Latest backup is %u", latest_backup_id_);
// delete any backups that claim to be later than latest
std::vector<BackupID> later_ids;
for (auto itr = backups_.lower_bound(latest_backup_id_ + 1);
itr != backups_.end(); itr++) {
Log(options_.info_log,
"Found backup claiming to be later than latest: %" PRIu32, itr->first);
later_ids.push_back(itr->first);
}
for (auto id : later_ids) {
Status s;
if (!read_only_) {
s = DeleteBackup(id);
} else {
auto backup = backups_.find(id);
// We just found it couple of lines earlier!
assert(backup != backups_.end());
s = backup->second->Delete(false);
backups_.erase(backup);
}
if (!s.ok()) {
Log(options_.info_log, "Failed deleting backup %" PRIu32 " -- %s", id,
s.ToString().c_str());
}
}
if (!read_only_) {
auto s = PutLatestBackupFileContents(latest_backup_id_);
if (!s.ok()) {
return s;
}
}
// set up threads perform copies from files_to_copy_ in the background
for (int t = 0; t < options_.max_background_operations; t++) {
threads_.emplace_back([&]() {
CopyWorkItem work_item;
while (files_to_copy_.read(work_item)) {
CopyResult result;
result.status = CopyFile(work_item.src_path,
work_item.dst_path,
work_item.src_env,
work_item.dst_env,
work_item.sync,
work_item.rate_limiter,
&result.size,
&result.checksum_value,
work_item.size_limit);
work_item.result.set_value(std::move(result));
}
});
}
Log(options_.info_log, "Initialized BackupEngine");
return Status::OK();
}
Status BackupEngineImpl::CreateNewBackup(DB* db, bool flush_before_backup) {
assert(initialized_);
if (options_.max_background_operations > 1 &&
options_.backup_rate_limit != 0) {
return Status::InvalidArgument(
"Multi-threaded backups cannot use a backup_rate_limit");
}
assert(!read_only_);
Status s;
std::vector<std::string> live_files;
VectorLogPtr live_wal_files;
uint64_t manifest_file_size = 0;
uint64_t sequence_number = db->GetLatestSequenceNumber();
s = db->DisableFileDeletions();
if (s.ok()) {
// this will return live_files prefixed with "/"
s = db->GetLiveFiles(live_files, &manifest_file_size, flush_before_backup);
}
// if we didn't flush before backup, we need to also get WAL files
if (s.ok() && !flush_before_backup && options_.backup_log_files) {
// returns file names prefixed with "/"
s = db->GetSortedWalFiles(live_wal_files);
}
if (!s.ok()) {
db->EnableFileDeletions(false);
return s;
}
BackupID new_backup_id = latest_backup_id_ + 1;
assert(backups_.find(new_backup_id) == backups_.end());
auto ret = backups_.insert(std::move(
std::make_pair(new_backup_id, unique_ptr<BackupMeta>(new BackupMeta(
GetBackupMetaFile(new_backup_id),
&backuped_file_infos_, backup_env_)))));
assert(ret.second == true);
auto& new_backup = ret.first->second;
new_backup->RecordTimestamp();
new_backup->SetSequenceNumber(sequence_number);
auto start_backup = backup_env_-> NowMicros();
Log(options_.info_log, "Started the backup process -- creating backup %u",
new_backup_id);
// create temporary private dir
s = backup_env_->CreateDir(
GetAbsolutePath(GetPrivateFileRel(new_backup_id, true)));
unique_ptr<BackupRateLimiter> rate_limiter;
if (options_.backup_rate_limit > 0) {
copy_file_buffer_size_ = options_.backup_rate_limit / 10;
rate_limiter.reset(new BackupRateLimiter(db_env_,
options_.backup_rate_limit, copy_file_buffer_size_));
}
// A set into which we will insert the dst_paths that are calculated for live
// files and live WAL files.
// This is used to check whether a live files shares a dst_path with another
// live file.
std::unordered_set<std::string> live_dst_paths;
live_dst_paths.reserve(live_files.size() + live_wal_files.size());
std::vector<BackupAfterCopyWorkItem> backup_items_to_finish;
// Add a CopyWorkItem to the channel for each live file
for (size_t i = 0; s.ok() && i < live_files.size(); ++i) {
uint64_t number;
FileType type;
bool ok = ParseFileName(live_files[i], &number, &type);
if (!ok) {
assert(false);
return Status::Corruption("Can't parse file name. This is very bad");
}
// we should only get sst, manifest and current files here
assert(type == kTableFile || type == kDescriptorFile ||
type == kCurrentFile);
// rules:
// * if it's kTableFile, then it's shared
// * if it's kDescriptorFile, limit the size to manifest_file_size
s = AddBackupFileWorkItem(
live_dst_paths,
backup_items_to_finish,
new_backup_id,
options_.share_table_files && type == kTableFile,
db->GetName(),
live_files[i],
rate_limiter.get(),
(type == kDescriptorFile) ? manifest_file_size : 0,
options_.share_files_with_checksum && type == kTableFile);
}
// Add a CopyWorkItem to the channel for each WAL file
for (size_t i = 0; s.ok() && i < live_wal_files.size(); ++i) {
if (live_wal_files[i]->Type() == kAliveLogFile) {
// we only care about live log files
// copy the file into backup_dir/files/<new backup>/
s = AddBackupFileWorkItem(live_dst_paths,
backup_items_to_finish,
new_backup_id,
false, /* not shared */
db->GetOptions().wal_dir,
live_wal_files[i]->PathName(),
rate_limiter.get());
}
}
Status item_status;
for (auto& item : backup_items_to_finish) {
item.result.wait();
auto result = item.result.get();
item_status = result.status;
if (item_status.ok() && item.shared && item.needed_to_copy) {
item_status = item.backup_env->RenameFile(item.dst_path_tmp,
item.dst_path);
}
if (item_status.ok()) {
item_status = new_backup.get()->AddFile(
std::make_shared<FileInfo>(item.dst_relative,
result.size,
result.checksum_value));
}
if (!item_status.ok()) {
s = item_status;
}
}
// we copied all the files, enable file deletions
db->EnableFileDeletions(false);
if (s.ok()) {
// move tmp private backup to real backup folder
Log(options_.info_log,
"Moving tmp backup directory to the real one: %s -> %s\n",
GetAbsolutePath(GetPrivateFileRel(new_backup_id, true)).c_str(),
GetAbsolutePath(GetPrivateFileRel(new_backup_id, false)).c_str());
s = backup_env_->RenameFile(
GetAbsolutePath(GetPrivateFileRel(new_backup_id, true)), // tmp
GetAbsolutePath(GetPrivateFileRel(new_backup_id, false)));
}
auto backup_time = backup_env_->NowMicros() - start_backup;
if (s.ok()) {
// persist the backup metadata on the disk
s = new_backup->StoreToFile(options_.sync);
}
if (s.ok()) {
// install the newly created backup meta! (atomic)
s = PutLatestBackupFileContents(new_backup_id);
}
if (s.ok() && options_.sync) {
unique_ptr<Directory> backup_private_directory;
backup_env_->NewDirectory(
GetAbsolutePath(GetPrivateFileRel(new_backup_id, false)),
&backup_private_directory);
if (backup_private_directory != nullptr) {
backup_private_directory->Fsync();
}
if (private_directory_ != nullptr) {
private_directory_->Fsync();
}
if (meta_directory_ != nullptr) {
meta_directory_->Fsync();
}
if (shared_directory_ != nullptr) {
shared_directory_->Fsync();
}
if (backup_directory_ != nullptr) {
backup_directory_->Fsync();
}
}
if (s.ok()) {
backup_statistics_.IncrementNumberSuccessBackup();
}
if (!s.ok()) {
backup_statistics_.IncrementNumberFailBackup();
// clean all the files we might have created
Log(options_.info_log, "Backup failed -- %s", s.ToString().c_str());
Log(options_.info_log, "Backup Statistics %s\n",
backup_statistics_.ToString().c_str());
// delete files that we might have already written
DeleteBackup(new_backup_id);
GarbageCollect();
return s;
}
// here we know that we succeeded and installed the new backup
// in the LATEST_BACKUP file
latest_backup_id_ = new_backup_id;
Log(options_.info_log, "Backup DONE. All is good");
// backup_speed is in byte/second
double backup_speed = new_backup->GetSize() / (1.048576 * backup_time);
Log(options_.info_log, "Backup number of files: %u",
new_backup->GetNumberFiles());
char human_size[16];
AppendHumanBytes(new_backup->GetSize(), human_size, sizeof(human_size));
Log(options_.info_log, "Backup size: %s", human_size);
Log(options_.info_log, "Backup time: %" PRIu64 " microseconds", backup_time);
Log(options_.info_log, "Backup speed: %.3f MB/s", backup_speed);
Log(options_.info_log, "Backup Statistics %s",
backup_statistics_.ToString().c_str());
return s;
}
Status BackupEngineImpl::PurgeOldBackups(uint32_t num_backups_to_keep) {
assert(initialized_);
assert(!read_only_);
Log(options_.info_log, "Purging old backups, keeping %u",
num_backups_to_keep);
std::vector<BackupID> to_delete;
auto itr = backups_.begin();
while ((backups_.size() - to_delete.size()) > num_backups_to_keep) {
to_delete.push_back(itr->first);
itr++;
}
for (auto backup_id : to_delete) {
auto s = DeleteBackup(backup_id);
if (!s.ok()) {
return s;
}
}
return Status::OK();
}
Status BackupEngineImpl::DeleteBackup(BackupID backup_id) {
assert(initialized_);
assert(!read_only_);
Log(options_.info_log, "Deleting backup %u", backup_id);
auto backup = backups_.find(backup_id);
if (backup != backups_.end()) {
auto s = backup->second->Delete();
if (!s.ok()) {
return s;
}
backups_.erase(backup);
} else {
auto corrupt = corrupt_backups_.find(backup_id);
if (corrupt == corrupt_backups_.end()) {
return Status::NotFound("Backup not found");
}
auto s = corrupt->second.second->Delete();
if (!s.ok()) {
return s;
}
corrupt_backups_.erase(corrupt);
}
std::vector<std::string> to_delete;
for (auto& itr : backuped_file_infos_) {
if (itr.second->refs == 0) {
Status s = backup_env_->DeleteFile(GetAbsolutePath(itr.first));
Log(options_.info_log, "Deleting %s -- %s", itr.first.c_str(),
s.ToString().c_str());
to_delete.push_back(itr.first);
}
}
for (auto& td : to_delete) {
backuped_file_infos_.erase(td);
}
// take care of private dirs -- GarbageCollect() will take care of them
// if they are not empty
std::string private_dir = GetPrivateFileRel(backup_id);
Status s = backup_env_->DeleteDir(GetAbsolutePath(private_dir));
Log(options_.info_log, "Deleting private dir %s -- %s",
private_dir.c_str(), s.ToString().c_str());
return Status::OK();
}
void BackupEngineImpl::GetBackupInfo(std::vector<BackupInfo>* backup_info) {
assert(initialized_);
backup_info->reserve(backups_.size());
for (auto& backup : backups_) {
if (!backup.second->Empty()) {
backup_info->push_back(BackupInfo(
backup.first, backup.second->GetTimestamp(),
backup.second->GetSize(),
backup.second->GetNumberFiles()));
}
}
}
void
BackupEngineImpl::GetCorruptedBackups(
std::vector<BackupID>* corrupt_backup_ids) {
assert(initialized_);
corrupt_backup_ids->reserve(corrupt_backups_.size());
for (auto& backup : corrupt_backups_) {
corrupt_backup_ids->push_back(backup.first);
}
}
Status BackupEngineImpl::RestoreDBFromBackup(
BackupID backup_id, const std::string& db_dir, const std::string& wal_dir,
const RestoreOptions& restore_options) {
assert(initialized_);
if (options_.max_background_operations > 1 &&
options_.restore_rate_limit != 0) {
return Status::InvalidArgument(
"Multi-threaded restores cannot use a restore_rate_limit");
}
auto corrupt_itr = corrupt_backups_.find(backup_id);
if (corrupt_itr != corrupt_backups_.end()) {
return corrupt_itr->second.first;
}
auto backup_itr = backups_.find(backup_id);
if (backup_itr == backups_.end()) {
return Status::NotFound("Backup not found");
}
auto& backup = backup_itr->second;
if (backup->Empty()) {
return Status::NotFound("Backup not found");
}
Log(options_.info_log, "Restoring backup id %u\n", backup_id);
Log(options_.info_log, "keep_log_files: %d\n",
static_cast<int>(restore_options.keep_log_files));
// just in case. Ignore errors
db_env_->CreateDirIfMissing(db_dir);
db_env_->CreateDirIfMissing(wal_dir);
if (restore_options.keep_log_files) {
// delete files in db_dir, but keep all the log files
DeleteChildren(db_dir, 1 << kLogFile);
// move all the files from archive dir to wal_dir
std::string archive_dir = ArchivalDirectory(wal_dir);
std::vector<std::string> archive_files;
db_env_->GetChildren(archive_dir, &archive_files); // ignore errors
for (const auto& f : archive_files) {
uint64_t number;
FileType type;
bool ok = ParseFileName(f, &number, &type);
if (ok && type == kLogFile) {
Log(options_.info_log, "Moving log file from archive/ to wal_dir: %s",
f.c_str());
Status s =
db_env_->RenameFile(archive_dir + "/" + f, wal_dir + "/" + f);
if (!s.ok()) {
// if we can't move log file from archive_dir to wal_dir,
// we should fail, since it might mean data loss
return s;
}
}
}
} else {
DeleteChildren(wal_dir);
DeleteChildren(ArchivalDirectory(wal_dir));
DeleteChildren(db_dir);
}
unique_ptr<BackupRateLimiter> rate_limiter;
if (options_.restore_rate_limit > 0) {
copy_file_buffer_size_ = options_.restore_rate_limit / 10;
rate_limiter.reset(new BackupRateLimiter(db_env_,
options_.restore_rate_limit, copy_file_buffer_size_));
}
Status s;
std::vector<RestoreAfterCopyWorkItem> restore_items_to_finish;
for (const auto& file_info : backup->GetFiles()) {
const std::string &file = file_info->filename;
std::string dst;
// 1. extract the filename
size_t slash = file.find_last_of('/');
// file will either be shared/<file>, shared_checksum/<file_crc32_size>
// or private/<number>/<file>
assert(slash != std::string::npos);
dst = file.substr(slash + 1);
// if the file was in shared_checksum, extract the real file name
// in this case the file is <number>_<checksum>_<size>.<type>
if (file.substr(0, slash) == GetSharedChecksumDirRel()) {
dst = GetFileFromChecksumFile(dst);
}
// 2. find the filetype
uint64_t number;
FileType type;
bool ok = ParseFileName(dst, &number, &type);
if (!ok) {
return Status::Corruption("Backup corrupted");
}
// 3. Construct the final path
// kLogFile lives in wal_dir and all the rest live in db_dir
dst = ((type == kLogFile) ? wal_dir : db_dir) +
"/" + dst;
Log(options_.info_log, "Restoring %s to %s\n", file.c_str(), dst.c_str());
CopyWorkItem copy_work_item(GetAbsolutePath(file),
dst,
backup_env_,
db_env_,
false,
rate_limiter.get(),
0 /* size_limit */);
RestoreAfterCopyWorkItem after_copy_work_item(
copy_work_item.result.get_future(),
file_info->checksum_value);
files_to_copy_.write(std::move(copy_work_item));
restore_items_to_finish.push_back(std::move(after_copy_work_item));
}
Status item_status;
for (auto& item : restore_items_to_finish) {
item.result.wait();
auto result = item.result.get();
item_status = result.status;
// Note: It is possible that both of the following bad-status cases occur
// during copying. But, we only return one status.
if (!item_status.ok()) {
s = item_status;
break;
} else if (item.checksum_value != result.checksum_value) {
s = Status::Corruption("Checksum check failed");
break;
}
}
Log(options_.info_log, "Restoring done -- %s\n", s.ToString().c_str());
return s;
}
// latest backup id is an ASCII representation of latest backup id
Status BackupEngineImpl::GetLatestBackupFileContents(uint32_t* latest_backup) {
Status s;
unique_ptr<SequentialFile> file;
s = backup_env_->NewSequentialFile(GetLatestBackupFile(),
&file,
EnvOptions());
if (!s.ok()) {
return s;
}
char buf[11];
Slice data;
unique_ptr<SequentialFileReader> file_reader(
new SequentialFileReader(std::move(file)));
s = file_reader->Read(10, &data, buf);
if (!s.ok() || data.size() == 0) {
return s.ok() ? Status::Corruption("Latest backup file corrupted") : s;
}
buf[data.size()] = 0;
*latest_backup = 0;
sscanf(data.data(), "%u", latest_backup);
if (backup_env_->FileExists(GetBackupMetaFile(*latest_backup)) == false) {
s = Status::Corruption("Latest backup file corrupted");
}
return Status::OK();
}
// this operation HAS to be atomic
// writing 4 bytes to the file is atomic alright, but we should *never*
// do something like 1. delete file, 2. write new file
// We write to a tmp file and then atomically rename
Status BackupEngineImpl::PutLatestBackupFileContents(uint32_t latest_backup) {
assert(!read_only_);
Status s;
unique_ptr<WritableFile> file;
EnvOptions env_options;
env_options.use_mmap_writes = false;
s = backup_env_->NewWritableFile(GetLatestBackupFile(true),
&file,
env_options);
if (!s.ok()) {
backup_env_->DeleteFile(GetLatestBackupFile(true));
return s;
}
unique_ptr<WritableFileWriter> file_writer(
new WritableFileWriter(std::move(file), env_options));
char file_contents[10];
int len = sprintf(file_contents, "%u\n", latest_backup);
s = file_writer->Append(Slice(file_contents, len));
if (s.ok() && options_.sync) {
file_writer->Sync(false);
}
if (s.ok()) {
s = file_writer->Close();
}
if (s.ok()) {
// atomically replace real file with new tmp
s = backup_env_->RenameFile(GetLatestBackupFile(true),
GetLatestBackupFile(false));
}
return s;
}
Status BackupEngineImpl::CopyFile(
const std::string& src,
const std::string& dst, Env* src_env,
Env* dst_env, bool sync,
BackupRateLimiter* rate_limiter, uint64_t* size,
uint32_t* checksum_value,
uint64_t size_limit) {
Status s;
unique_ptr<WritableFile> dst_file;
unique_ptr<SequentialFile> src_file;
EnvOptions env_options;
env_options.use_mmap_writes = false;
env_options.use_os_buffer = false;
if (size != nullptr) {
*size = 0;
}
if (checksum_value != nullptr) {
*checksum_value = 0;
}
// Check if size limit is set. if not, set it to very big number
if (size_limit == 0) {
size_limit = std::numeric_limits<uint64_t>::max();
}
s = src_env->NewSequentialFile(src, &src_file, env_options);
if (s.ok()) {
s = dst_env->NewWritableFile(dst, &dst_file, env_options);
}
if (!s.ok()) {
return s;
}
unique_ptr<WritableFileWriter> dest_writer(
new WritableFileWriter(std::move(dst_file), env_options));
unique_ptr<SequentialFileReader> src_reader(
new SequentialFileReader(std::move(src_file)));
unique_ptr<char[]> buf(new char[copy_file_buffer_size_]);
Slice data;
do {
if (stop_backup_.load(std::memory_order_acquire)) {
return Status::Incomplete("Backup stopped");
}
size_t buffer_to_read = (copy_file_buffer_size_ < size_limit) ?
copy_file_buffer_size_ : size_limit;
s = src_reader->Read(buffer_to_read, &data, buf.get());
size_limit -= data.size();
if (!s.ok()) {
return s;
}
if (size != nullptr) {
*size += data.size();
}
if (checksum_value != nullptr) {
*checksum_value = crc32c::Extend(*checksum_value, data.data(),
data.size());
}
s = dest_writer->Append(data);
if (rate_limiter != nullptr) {
rate_limiter->ReportAndWait(data.size());
}
} while (s.ok() && data.size() > 0 && size_limit > 0);
if (s.ok() && sync) {
s = dest_writer->Sync(false);
}
return s;
}
// src_fname will always start with "/"
Status BackupEngineImpl::AddBackupFileWorkItem(
std::unordered_set<std::string>& live_dst_paths,
std::vector<BackupAfterCopyWorkItem>& backup_items_to_finish,
BackupID backup_id,
bool shared,
const std::string& src_dir,
const std::string& src_fname,
BackupRateLimiter* rate_limiter,
uint64_t size_limit,
bool shared_checksum) {
assert(src_fname.size() > 0 && src_fname[0] == '/');
std::string dst_relative = src_fname.substr(1);
std::string dst_relative_tmp;
Status s;
uint64_t size;
uint32_t checksum_value = 0;
if (shared && shared_checksum) {
// add checksum and file length to the file name
s = CalculateChecksum(src_dir + src_fname,
db_env_,
size_limit,
&checksum_value);
if (s.ok()) {
s = db_env_->GetFileSize(src_dir + src_fname, &size);
}
if (!s.ok()) {
return s;
}
dst_relative = GetSharedFileWithChecksum(dst_relative, checksum_value,
size);
dst_relative_tmp = GetSharedFileWithChecksumRel(dst_relative, true);
dst_relative = GetSharedFileWithChecksumRel(dst_relative, false);
} else if (shared) {
dst_relative_tmp = GetSharedFileRel(dst_relative, true);
dst_relative = GetSharedFileRel(dst_relative, false);
} else {
dst_relative_tmp = GetPrivateFileRel(backup_id, true, dst_relative);
dst_relative = GetPrivateFileRel(backup_id, false, dst_relative);
}
std::string dst_path = GetAbsolutePath(dst_relative);
std::string dst_path_tmp = GetAbsolutePath(dst_relative_tmp);
// if it's shared, we also need to check if it exists -- if it does, no need
// to copy it again.
bool need_to_copy = true;
// true if dst_path is the same path as another live file
const bool same_path =
live_dst_paths.find(dst_path) != live_dst_paths.end();
if (shared && (backup_env_->FileExists(dst_path) || same_path)) {
need_to_copy = false;
if (shared_checksum) {
Log(options_.info_log,
"%s already present, with checksum %u and size %" PRIu64,
src_fname.c_str(), checksum_value, size);
} else if (backuped_file_infos_.find(dst_relative) ==
backuped_file_infos_.end() && !same_path) {
// file already exists, but it's not referenced by any backup. overwrite
// the file
Log(options_.info_log,
"%s already present, but not referenced by any backup. We will "
"overwrite the file.",
src_fname.c_str());
need_to_copy = true;
backup_env_->DeleteFile(dst_path);
} else {
// the file is present and referenced by a backup
db_env_->GetFileSize(src_dir + src_fname, &size); // Ignore error
Log(options_.info_log, "%s already present, calculate checksum",
src_fname.c_str());
s = CalculateChecksum(src_dir + src_fname, db_env_, size_limit,
&checksum_value);
}
}
live_dst_paths.insert(dst_path);
if (need_to_copy) {
Log(options_.info_log, "Copying %s to %s", src_fname.c_str(),
dst_path_tmp.c_str());
CopyWorkItem copy_work_item(src_dir + src_fname,
dst_path_tmp,
db_env_,
backup_env_,
options_.sync,
rate_limiter,
size_limit);
BackupAfterCopyWorkItem after_copy_work_item(
copy_work_item.result.get_future(),
shared,
need_to_copy,
backup_env_,
dst_path_tmp,
dst_path,
dst_relative);
files_to_copy_.write(std::move(copy_work_item));
backup_items_to_finish.push_back(std::move(after_copy_work_item));
} else {
std::promise<CopyResult> promise_result;
BackupAfterCopyWorkItem after_copy_work_item(
promise_result.get_future(),
shared,
need_to_copy,
backup_env_,
dst_path_tmp,
dst_path,
dst_relative);
backup_items_to_finish.push_back(std::move(after_copy_work_item));
CopyResult result;
result.status = s;
result.size = size;
result.checksum_value = checksum_value;
promise_result.set_value(std::move(result));
}
return s;
}
Status BackupEngineImpl::CalculateChecksum(const std::string& src, Env* src_env,
uint64_t size_limit,
uint32_t* checksum_value) {
*checksum_value = 0;
if (size_limit == 0) {
size_limit = std::numeric_limits<uint64_t>::max();
}
EnvOptions env_options;
env_options.use_mmap_writes = false;
env_options.use_os_buffer = false;
std::unique_ptr<SequentialFile> src_file;
Status s = src_env->NewSequentialFile(src, &src_file, env_options);
if (!s.ok()) {
return s;
}
unique_ptr<SequentialFileReader> src_reader(
new SequentialFileReader(std::move(src_file)));
std::unique_ptr<char[]> buf(new char[copy_file_buffer_size_]);
Slice data;
do {
if (stop_backup_.load(std::memory_order_acquire)) {
return Status::Incomplete("Backup stopped");
}
size_t buffer_to_read = (copy_file_buffer_size_ < size_limit) ?
copy_file_buffer_size_ : size_limit;
s = src_reader->Read(buffer_to_read, &data, buf.get());
if (!s.ok()) {
return s;
}
size_limit -= data.size();
*checksum_value = crc32c::Extend(*checksum_value, data.data(), data.size());
} while (data.size() > 0 && size_limit > 0);
return s;
}
void BackupEngineImpl::DeleteChildren(const std::string& dir,
uint32_t file_type_filter) {
std::vector<std::string> children;
db_env_->GetChildren(dir, &children); // ignore errors
for (const auto& f : children) {
uint64_t number;
FileType type;
bool ok = ParseFileName(f, &number, &type);
if (ok && (file_type_filter & (1 << type))) {
// don't delete this file
continue;
}
db_env_->DeleteFile(dir + "/" + f); // ignore errors
}
}
Status BackupEngineImpl::GarbageCollect() {
assert(!read_only_);
Log(options_.info_log, "Starting garbage collection");
// delete obsolete shared files
std::vector<std::string> shared_children;
{
auto s = backup_env_->GetChildren(GetAbsolutePath(GetSharedFileRel()),
&shared_children);
if (!s.ok()) {
return s;
}
}
for (auto& child : shared_children) {
std::string rel_fname = GetSharedFileRel(child);
auto child_itr = backuped_file_infos_.find(rel_fname);
// if it's not refcounted, delete it
if (child_itr == backuped_file_infos_.end() ||
child_itr->second->refs == 0) {
// this might be a directory, but DeleteFile will just fail in that
// case, so we're good
Status s = backup_env_->DeleteFile(GetAbsolutePath(rel_fname));
Log(options_.info_log, "Deleting %s -- %s", rel_fname.c_str(),
s.ToString().c_str());
backuped_file_infos_.erase(rel_fname);
}
}
// delete obsolete private files
std::vector<std::string> private_children;
{
auto s = backup_env_->GetChildren(GetAbsolutePath(GetPrivateDirRel()),
&private_children);
if (!s.ok()) {
return s;
}
}
for (auto& child : private_children) {
BackupID backup_id = 0;
bool tmp_dir = child.find(".tmp") != std::string::npos;
sscanf(child.c_str(), "%u", &backup_id);
if (!tmp_dir && // if it's tmp_dir, delete it
(backup_id == 0 || backups_.find(backup_id) != backups_.end())) {
// it's either not a number or it's still alive. continue
continue;
}
// here we have to delete the dir and all its children
std::string full_private_path =
GetAbsolutePath(GetPrivateFileRel(backup_id, tmp_dir));
std::vector<std::string> subchildren;
backup_env_->GetChildren(full_private_path, &subchildren);
for (auto& subchild : subchildren) {
Status s = backup_env_->DeleteFile(full_private_path + subchild);
Log(options_.info_log, "Deleting %s -- %s",
(full_private_path + subchild).c_str(), s.ToString().c_str());
}
// finally delete the private dir
Status s = backup_env_->DeleteDir(full_private_path);
Log(options_.info_log, "Deleting dir %s -- %s", full_private_path.c_str(),
s.ToString().c_str());
}
return Status::OK();
}
// ------- BackupMeta class --------
Status BackupEngineImpl::BackupMeta::AddFile(
std::shared_ptr<FileInfo> file_info) {
auto itr = file_infos_->find(file_info->filename);
if (itr == file_infos_->end()) {
auto ret = file_infos_->insert({file_info->filename, file_info});
if (ret.second) {
itr = ret.first;
itr->second->refs = 1;
} else {
// if this happens, something is seriously wrong
return Status::Corruption("In memory metadata insertion error");
}
} else {
if (itr->second->checksum_value != file_info->checksum_value) {
return Status::Corruption(
"Checksum mismatch for existing backup file. Delete old backups and "
"try again.");
}
++itr->second->refs; // increase refcount if already present
}
size_ += file_info->size;
files_.push_back(itr->second);
return Status::OK();
}
Status BackupEngineImpl::BackupMeta::Delete(bool delete_meta) {
Status s;
for (const auto& file : files_) {
--file->refs; // decrease refcount
}
files_.clear();
// delete meta file
if (delete_meta && env_->FileExists(meta_filename_)) {
s = env_->DeleteFile(meta_filename_);
}
timestamp_ = 0;
return s;
}
// each backup meta file is of the format:
// <timestamp>
// <seq number>
// <number of files>
// <file1> <crc32(literal string)> <crc32_value>
// <file2> <crc32(literal string)> <crc32_value>
// ...
Status BackupEngineImpl::BackupMeta::LoadFromFile(
const std::string& backup_dir) {
assert(Empty());
Status s;
unique_ptr<SequentialFile> backup_meta_file;
s = env_->NewSequentialFile(meta_filename_, &backup_meta_file, EnvOptions());
if (!s.ok()) {
return s;
}
unique_ptr<SequentialFileReader> backup_meta_reader(
new SequentialFileReader(std::move(backup_meta_file)));
unique_ptr<char[]> buf(new char[max_backup_meta_file_size_ + 1]);
Slice data;
s = backup_meta_reader->Read(max_backup_meta_file_size_, &data, buf.get());
if (!s.ok() || data.size() == max_backup_meta_file_size_) {
return s.ok() ? Status::Corruption("File size too big") : s;
}
buf[data.size()] = 0;
uint32_t num_files = 0;
char *next;
timestamp_ = strtoull(data.data(), &next, 10);
data.remove_prefix(next - data.data() + 1); // +1 for '\n'
sequence_number_ = strtoull(data.data(), &next, 10);
data.remove_prefix(next - data.data() + 1); // +1 for '\n'
num_files = static_cast<uint32_t>(strtoul(data.data(), &next, 10));
data.remove_prefix(next - data.data() + 1); // +1 for '\n'
std::vector<std::shared_ptr<FileInfo>> files;
Slice checksum_prefix("crc32 ");
for (uint32_t i = 0; s.ok() && i < num_files; ++i) {
auto line = GetSliceUntil(&data, '\n');
std::string filename = GetSliceUntil(&line, ' ').ToString();
uint64_t size;
const std::shared_ptr<FileInfo> file_info = GetFile(filename);
if (file_info) {
size = file_info->size;
} else {
s = env_->GetFileSize(backup_dir + "/" + filename, &size);
if (!s.ok()) {
return s;
}
}
if (line.empty()) {
return Status::Corruption("File checksum is missing for " + filename +
" in " + meta_filename_);
}
uint32_t checksum_value = 0;
if (line.starts_with(checksum_prefix)) {
line.remove_prefix(checksum_prefix.size());
checksum_value = static_cast<uint32_t>(
strtoul(line.data(), nullptr, 10));
if (line != rocksdb::ToString(checksum_value)) {
return Status::Corruption("Invalid checksum value for " + filename +
" in " + meta_filename_);
}
} else {
return Status::Corruption("Unknown checksum type for " + filename +
" in " + meta_filename_);
}
files.emplace_back(new FileInfo(filename, size, checksum_value));
}
if (s.ok() && data.size() > 0) {
// file has to be read completely. if not, we count it as corruption
s = Status::Corruption("Tailing data in backup meta file in " +
meta_filename_);
}
if (s.ok()) {
files_.reserve(files.size());
for (const auto& file_info : files) {
s = AddFile(file_info);
if (!s.ok()) {
break;
}
}
}
return s;
}
Status BackupEngineImpl::BackupMeta::StoreToFile(bool sync) {
Status s;
unique_ptr<WritableFile> backup_meta_file;
EnvOptions env_options;
env_options.use_mmap_writes = false;
s = env_->NewWritableFile(meta_filename_ + ".tmp", &backup_meta_file,
env_options);
if (!s.ok()) {
return s;
}
unique_ptr<char[]> buf(new char[max_backup_meta_file_size_]);
int len = 0, buf_size = max_backup_meta_file_size_;
len += snprintf(buf.get(), buf_size, "%" PRId64 "\n", timestamp_);
len += snprintf(buf.get() + len, buf_size - len, "%" PRIu64 "\n",
sequence_number_);
len += snprintf(buf.get() + len, buf_size - len, "%" ROCKSDB_PRIszt "\n",
files_.size());
for (const auto& file : files_) {
// use crc32 for now, switch to something else if needed
len += snprintf(buf.get() + len, buf_size - len, "%s crc32 %u\n",
file->filename.c_str(), file->checksum_value);
}
s = backup_meta_file->Append(Slice(buf.get(), (size_t)len));
if (s.ok() && sync) {
s = backup_meta_file->Sync();
}
if (s.ok()) {
s = backup_meta_file->Close();
}
if (s.ok()) {
s = env_->RenameFile(meta_filename_ + ".tmp", meta_filename_);
}
return s;
}
// -------- BackupEngineReadOnlyImpl ---------
class BackupEngineReadOnlyImpl : public BackupEngineReadOnly {
public:
BackupEngineReadOnlyImpl(Env* db_env, const BackupableDBOptions& options)
: backup_engine_(new BackupEngineImpl(db_env, options, true)) {}
virtual ~BackupEngineReadOnlyImpl() {}
virtual void GetBackupInfo(std::vector<BackupInfo>* backup_info) override {
backup_engine_->GetBackupInfo(backup_info);
}
virtual void GetCorruptedBackups(
std::vector<BackupID>* corrupt_backup_ids) override {
backup_engine_->GetCorruptedBackups(corrupt_backup_ids);
}
virtual Status RestoreDBFromBackup(
BackupID backup_id, const std::string& db_dir, const std::string& wal_dir,
const RestoreOptions& restore_options = RestoreOptions()) override {
return backup_engine_->RestoreDBFromBackup(backup_id, db_dir, wal_dir,
restore_options);
}
virtual Status RestoreDBFromLatestBackup(
const std::string& db_dir, const std::string& wal_dir,
const RestoreOptions& restore_options = RestoreOptions()) override {
return backup_engine_->RestoreDBFromLatestBackup(db_dir, wal_dir,
restore_options);
}
Status Initialize() { return backup_engine_->Initialize(); }
private:
std::unique_ptr<BackupEngineImpl> backup_engine_;
};
Status BackupEngineReadOnly::Open(Env* env, const BackupableDBOptions& options,
BackupEngineReadOnly** backup_engine_ptr) {
if (options.destroy_old_data) {
return Status::InvalidArgument(
"Can't destroy old data with ReadOnly BackupEngine");
}
std::unique_ptr<BackupEngineReadOnlyImpl> backup_engine(
new BackupEngineReadOnlyImpl(env, options));
auto s = backup_engine->Initialize();
if (!s.ok()) {
*backup_engine_ptr = nullptr;
return s;
}
*backup_engine_ptr = backup_engine.release();
return Status::OK();
}
// --- BackupableDB methods --------
BackupableDB::BackupableDB(DB* db, const BackupableDBOptions& options)
: StackableDB(db) {
auto backup_engine_impl = new BackupEngineImpl(db->GetEnv(), options);
status_ = backup_engine_impl->Initialize();
backup_engine_ = backup_engine_impl;
}
BackupableDB::~BackupableDB() {
delete backup_engine_;
}
Status BackupableDB::CreateNewBackup(bool flush_before_backup) {
if (!status_.ok()) {
return status_;
}
return backup_engine_->CreateNewBackup(this, flush_before_backup);
}
void BackupableDB::GetBackupInfo(std::vector<BackupInfo>* backup_info) {
if (!status_.ok()) {
return;
}
backup_engine_->GetBackupInfo(backup_info);
}
void
BackupableDB::GetCorruptedBackups(std::vector<BackupID>* corrupt_backup_ids) {
if (!status_.ok()) {
return;
}
backup_engine_->GetCorruptedBackups(corrupt_backup_ids);
}
Status BackupableDB::PurgeOldBackups(uint32_t num_backups_to_keep) {
if (!status_.ok()) {
return status_;
}
return backup_engine_->PurgeOldBackups(num_backups_to_keep);
}
Status BackupableDB::DeleteBackup(BackupID backup_id) {
if (!status_.ok()) {
return status_;
}
return backup_engine_->DeleteBackup(backup_id);
}
void BackupableDB::StopBackup() {
backup_engine_->StopBackup();
}
Status BackupableDB::GarbageCollect() {
if (!status_.ok()) {
return status_;
}
return backup_engine_->GarbageCollect();
}
// --- RestoreBackupableDB methods ------
RestoreBackupableDB::RestoreBackupableDB(Env* db_env,
const BackupableDBOptions& options) {
auto backup_engine_impl = new BackupEngineImpl(db_env, options);
status_ = backup_engine_impl->Initialize();
backup_engine_ = backup_engine_impl;
}
RestoreBackupableDB::~RestoreBackupableDB() {
delete backup_engine_;
}
void
RestoreBackupableDB::GetBackupInfo(std::vector<BackupInfo>* backup_info) {
if (!status_.ok()) {
return;
}
backup_engine_->GetBackupInfo(backup_info);
}
void RestoreBackupableDB::GetCorruptedBackups(
std::vector<BackupID>* corrupt_backup_ids) {
if (!status_.ok()) {
return;
}
backup_engine_->GetCorruptedBackups(corrupt_backup_ids);
}
Status RestoreBackupableDB::RestoreDBFromBackup(
BackupID backup_id, const std::string& db_dir, const std::string& wal_dir,
const RestoreOptions& restore_options) {
if (!status_.ok()) {
return status_;
}
return backup_engine_->RestoreDBFromBackup(backup_id, db_dir, wal_dir,
restore_options);
}
Status RestoreBackupableDB::RestoreDBFromLatestBackup(
const std::string& db_dir, const std::string& wal_dir,
const RestoreOptions& restore_options) {
if (!status_.ok()) {
return status_;
}
return backup_engine_->RestoreDBFromLatestBackup(db_dir, wal_dir,
restore_options);
}
Status RestoreBackupableDB::PurgeOldBackups(uint32_t num_backups_to_keep) {
if (!status_.ok()) {
return status_;
}
return backup_engine_->PurgeOldBackups(num_backups_to_keep);
}
Status RestoreBackupableDB::DeleteBackup(BackupID backup_id) {
if (!status_.ok()) {
return status_;
}
return backup_engine_->DeleteBackup(backup_id);
}
Status RestoreBackupableDB::GarbageCollect() {
if (!status_.ok()) {
return status_;
}
return backup_engine_->GarbageCollect();
}
} // namespace rocksdb
#endif // ROCKSDB_LITE
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