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rocksdb/utilities/backupable/backupable_db.cc
agiardullo 064294081b Improved FileExists API 
Summary: Add new CheckFileExists method.  Considered changing the FileExists api but didn't want to break anyone's builds.

Test Plan: unit tests

Reviewers: yhchiang, igor, sdong

Reviewed By: sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D42003
2015-07-20 17:20:40 -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);
s = backup_env_->FileExists(GetBackupMetaFile(*latest_backup));
if (s.IsNotFound()) {
s = Status::Corruption("Latest backup file corrupted");
}
return s;
}
// 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();
bool file_exists = false;
if (shared && !same_path) {
Status exist = backup_env_->FileExists(dst_path);
if (exist.ok()) {
file_exists = true;
} else if (exist.IsNotFound()) {
file_exists = false;
} else {
assert(s.IsIOError());
return exist;
}
}
if (shared && (same_path || file_exists)) {
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) {
s = env_->FileExists(meta_filename_);
if (s.ok()) {
s = env_->DeleteFile(meta_filename_);
} else if (s.IsNotFound()) {
s = Status::OK(); // nothing to delete
}
}
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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