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rocksdb/utilities/backupable/backupable_db.cc
Andrew Kryczka a8a28da215 Avoid directory renames in BackupEngine 
Summary:
We used to name private directories like "1.tmp" while BackupEngine populated them, and then rename without the ".tmp" suffix (i.e., rename "1.tmp" to "1") after all files were copied. On glusterfs, directory renames like this require operations across many hosts, and partial failures have caused operational problems.

Fortunately we don't need to rename private directories. We already have a meta-file that uses the tempfile-rename pattern to commit a backup atomically after all its files have been successfully copied. So we can copy private files directly to their final location, so now there's no directory rename.
Closes https://github.com/facebook/rocksdb/pull/3749

Differential Revision: D7705610

Pulled By: ajkr

fbshipit-source-id: fd724a28dd2bf993ce323a5f2cb7e7d6980cc346
2018-04-20 17:28:33 -07:00

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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
//
// 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 "port/port.h"
#include "rocksdb/rate_limiter.h"
#include "rocksdb/transaction_log.h"
#include "util/channel.h"
#include "util/coding.h"
#include "util/crc32c.h"
#include "util/file_reader_writer.h"
#include "util/filename.h"
#include "util/logging.h"
#include "util/string_util.h"
#include "util/sync_point.h"
#include "utilities/checkpoint/checkpoint_impl.h"
#ifndef __STDC_FORMAT_MACROS
#define __STDC_FORMAT_MACROS
#endif // __STDC_FORMAT_MACROS
#include <inttypes.h>
#include <stdlib.h>
#include <algorithm>
#include <atomic>
#include <functional>
#include <future>
#include <limits>
#include <map>
#include <mutex>
#include <sstream>
#include <string>
#include <thread>
#include <unordered_map>
#include <unordered_set>
#include <vector>
namespace rocksdb {
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 {
ROCKS_LOG_INFO(logger, " Options.backup_dir: %s",
backup_dir.c_str());
ROCKS_LOG_INFO(logger, " Options.backup_env: %p", backup_env);
ROCKS_LOG_INFO(logger, " Options.share_table_files: %d",
static_cast<int>(share_table_files));
ROCKS_LOG_INFO(logger, " Options.info_log: %p", info_log);
ROCKS_LOG_INFO(logger, " Options.sync: %d",
static_cast<int>(sync));
ROCKS_LOG_INFO(logger, " Options.destroy_old_data: %d",
static_cast<int>(destroy_old_data));
ROCKS_LOG_INFO(logger, " Options.backup_log_files: %d",
static_cast<int>(backup_log_files));
ROCKS_LOG_INFO(logger, " Options.backup_rate_limit: %" PRIu64,
backup_rate_limit);
ROCKS_LOG_INFO(logger, " Options.restore_rate_limit: %" PRIu64,
restore_rate_limit);
ROCKS_LOG_INFO(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 CreateNewBackupWithMetadata(DB* db, const std::string& app_metadata,
bool flush_before_backup = false,
std::function<void()> progress_callback =
[]() {}) 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;
// The returned BackupInfos are in chronological order, which means the
// latest backup comes last.
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_valid_backup_id_, db_dir, wal_dir,
restore_options);
}
virtual Status VerifyBackup(BackupID backup_id) override;
Status Initialize();
private:
void DeleteChildren(const std::string& dir, uint32_t file_type_filter = 0);
// Extends the "result" map with pathname->size mappings for the contents of
// "dir" in "env". Pathnames are prefixed with "dir".
Status InsertPathnameToSizeBytes(
const std::string& dir, Env* env,
std::unordered_map<std::string, uint64_t>* result);
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, const std::string& meta_tmp_filename,
std::unordered_map<std::string, std::shared_ptr<FileInfo>>* file_infos,
Env* env)
: timestamp_(0),
sequence_number_(0),
size_(0),
meta_filename_(meta_filename),
meta_tmp_filename_(meta_tmp_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_;
}
const std::string& GetAppMetadata() const { return app_metadata_; }
void SetAppMetadata(const std::string& app_metadata) {
app_metadata_ = app_metadata;
}
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_;
}
// @param abs_path_to_size Pre-fetched file sizes (bytes).
Status LoadFromFile(
const std::string& backup_dir,
const std::unordered_map<std::string, uint64_t>& abs_path_to_size);
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 app_metadata_;
std::string const meta_filename_;
std::string const meta_tmp_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 std::string("shared/") + (tmp ? "." : "") + file +
(tmp ? ".tmp" : "");
}
inline std::string GetSharedFileWithChecksumRel(const std::string& file = "",
bool tmp = false) const {
assert(file.size() == 0 || file[0] != '/');
return GetSharedChecksumDirRel() + "/" + (tmp ? "." : "") + 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 GetBackupMetaDir() const {
return GetAbsolutePath("meta");
}
inline std::string GetBackupMetaFile(BackupID backup_id, bool tmp) const {
return GetBackupMetaDir() + "/" + (tmp ? "." : "") +
rocksdb::ToString(backup_id) + (tmp ? ".tmp" : "");
}
// If size_limit == 0, there is no size limit, copy everything.
//
// Exactly one of src and contents must be non-empty.
//
// @param src If non-empty, the file is copied from this pathname.
// @param contents If non-empty, the file will be created with these contents.
Status CopyOrCreateFile(const std::string& src, const std::string& dst,
const std::string& contents, Env* src_env,
Env* dst_env, bool sync, RateLimiter* rate_limiter,
uint64_t* size = nullptr,
uint32_t* checksum_value = nullptr,
uint64_t size_limit = 0,
std::function<void()> progress_callback = []() {});
Status CalculateChecksum(const std::string& src,
Env* src_env,
uint64_t size_limit,
uint32_t* checksum_value);
struct CopyOrCreateResult {
uint64_t size;
uint32_t checksum_value;
Status status;
};
// Exactly one of src_path and contents must be non-empty. If src_path is
// non-empty, the file is copied from this pathname. Otherwise, if contents is
// non-empty, the file will be created at dst_path with these contents.
struct CopyOrCreateWorkItem {
std::string src_path;
std::string dst_path;
std::string contents;
Env* src_env;
Env* dst_env;
bool sync;
RateLimiter* rate_limiter;
uint64_t size_limit;
std::promise<CopyOrCreateResult> result;
std::function<void()> progress_callback;
CopyOrCreateWorkItem()
: src_path(""),
dst_path(""),
contents(""),
src_env(nullptr),
dst_env(nullptr),
sync(false),
rate_limiter(nullptr),
size_limit(0) {}
CopyOrCreateWorkItem(const CopyOrCreateWorkItem&) = delete;
CopyOrCreateWorkItem& operator=(const CopyOrCreateWorkItem&) = delete;
CopyOrCreateWorkItem(CopyOrCreateWorkItem&& o) ROCKSDB_NOEXCEPT {
*this = std::move(o);
}
CopyOrCreateWorkItem& operator=(CopyOrCreateWorkItem&& o) ROCKSDB_NOEXCEPT {
src_path = std::move(o.src_path);
dst_path = std::move(o.dst_path);
contents = std::move(o.contents);
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);
progress_callback = std::move(o.progress_callback);
return *this;
}
CopyOrCreateWorkItem(std::string _src_path, std::string _dst_path,
std::string _contents, Env* _src_env, Env* _dst_env,
bool _sync, RateLimiter* _rate_limiter,
uint64_t _size_limit,
std::function<void()> _progress_callback = []() {})
: src_path(std::move(_src_path)),
dst_path(std::move(_dst_path)),
contents(std::move(_contents)),
src_env(_src_env),
dst_env(_dst_env),
sync(_sync),
rate_limiter(_rate_limiter),
size_limit(_size_limit),
progress_callback(_progress_callback) {}
};
struct BackupAfterCopyOrCreateWorkItem {
std::future<CopyOrCreateResult> result;
bool shared;
bool needed_to_copy;
Env* backup_env;
std::string dst_path_tmp;
std::string dst_path;
std::string dst_relative;
BackupAfterCopyOrCreateWorkItem()
: shared(false),
needed_to_copy(false),
backup_env(nullptr),
dst_path_tmp(""),
dst_path(""),
dst_relative("") {}
BackupAfterCopyOrCreateWorkItem(BackupAfterCopyOrCreateWorkItem&& o)
ROCKSDB_NOEXCEPT {
*this = std::move(o);
}
BackupAfterCopyOrCreateWorkItem& operator=(
BackupAfterCopyOrCreateWorkItem&& o) ROCKSDB_NOEXCEPT {
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;
}
BackupAfterCopyOrCreateWorkItem(std::future<CopyOrCreateResult>&& _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 RestoreAfterCopyOrCreateWorkItem {
std::future<CopyOrCreateResult> result;
uint32_t checksum_value;
RestoreAfterCopyOrCreateWorkItem()
: checksum_value(0) {}
RestoreAfterCopyOrCreateWorkItem(std::future<CopyOrCreateResult>&& _result,
uint32_t _checksum_value)
: result(std::move(_result)), checksum_value(_checksum_value) {}
RestoreAfterCopyOrCreateWorkItem(RestoreAfterCopyOrCreateWorkItem&& o)
ROCKSDB_NOEXCEPT {
*this = std::move(o);
}
RestoreAfterCopyOrCreateWorkItem& operator=(
RestoreAfterCopyOrCreateWorkItem&& o) ROCKSDB_NOEXCEPT {
result = std::move(o.result);
checksum_value = o.checksum_value;
return *this;
}
};
bool initialized_;
std::mutex byte_report_mutex_;
channel<CopyOrCreateWorkItem> files_to_copy_or_create_;
std::vector<port::Thread> threads_;
// Adds a file to the backup work queue to be copied or created if it doesn't
// already exist.
//
// Exactly one of src_dir and contents must be non-empty.
//
// @param src_dir If non-empty, the file in this directory named fname will be
// copied.
// @param fname Name of destination file and, in case of copy, source file.
// @param contents If non-empty, the file will be created with these contents.
Status AddBackupFileWorkItem(
std::unordered_set<std::string>& live_dst_paths,
std::vector<BackupAfterCopyOrCreateWorkItem>& backup_items_to_finish,
BackupID backup_id, bool shared, const std::string& src_dir,
const std::string& fname, // starts with "/"
RateLimiter* rate_limiter, uint64_t size_bytes, uint64_t size_limit = 0,
bool shared_checksum = false,
std::function<void()> progress_callback = []() {},
const std::string& contents = std::string());
// backup state data
BackupID latest_backup_id_;
BackupID latest_valid_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_;
static const size_t kMaxAppMetaSize = 1024 * 1024; // 1MB
};
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),
latest_backup_id_(0),
latest_valid_backup_id_(0),
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) {
if (options_.backup_rate_limiter == nullptr &&
options_.backup_rate_limit > 0) {
options_.backup_rate_limiter.reset(
NewGenericRateLimiter(options_.backup_rate_limit));
}
if (options_.restore_rate_limiter == nullptr &&
options_.restore_rate_limit > 0) {
options_.restore_rate_limiter.reset(
NewGenericRateLimiter(options_.restore_rate_limit));
}
}
BackupEngineImpl::~BackupEngineImpl() {
files_to_copy_or_create_.sendEof();
for (auto& t : threads_) {
t.join();
}
LogFlush(options_.info_log);
}
Status BackupEngineImpl::Initialize() {
assert(!initialized_);
initialized_ = true;
if (read_only_) {
ROCKS_LOG_INFO(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.IsNotFound()) {
return Status::NotFound(GetBackupMetaDir() + " is missing");
} else if (!s.ok()) {
return s;
}
}
// create backups_ structure
for (auto& file : backup_meta_files) {
if (file == "." || file == "..") {
continue;
}
ROCKS_LOG_INFO(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);
ROCKS_LOG_INFO(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::make_pair(
backup_id, unique_ptr<BackupMeta>(new BackupMeta(
GetBackupMetaFile(backup_id, false /* tmp */),
GetBackupMetaFile(backup_id, true /* tmp */),
&backuped_file_infos_, backup_env_))));
}
latest_backup_id_ = 0;
latest_valid_backup_id_ = 0;
if (options_.destroy_old_data) { // Destroy old data
assert(!read_only_);
ROCKS_LOG_INFO(
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;
}
} else { // Load data from storage
std::unordered_map<std::string, uint64_t> abs_path_to_size;
for (const auto& rel_dir :
{GetSharedFileRel(), GetSharedFileWithChecksumRel()}) {
const auto abs_dir = GetAbsolutePath(rel_dir);
InsertPathnameToSizeBytes(abs_dir, backup_env_, &abs_path_to_size);
}
// load the backups if any, until valid_backups_to_open of the latest
// non-corrupted backups have been successfully opened.
int valid_backups_to_open = options_.max_valid_backups_to_open;
for (auto backup_iter = backups_.rbegin();
backup_iter != backups_.rend();
++backup_iter) {
assert(latest_backup_id_ == 0 || latest_backup_id_ > backup_iter->first);
if (latest_backup_id_ == 0) {
latest_backup_id_ = backup_iter->first;
}
if (valid_backups_to_open == 0) {
break;
}
InsertPathnameToSizeBytes(
GetAbsolutePath(GetPrivateFileRel(backup_iter->first)), backup_env_,
&abs_path_to_size);
Status s = backup_iter->second->LoadFromFile(options_.backup_dir,
abs_path_to_size);
if (s.IsCorruption()) {
ROCKS_LOG_INFO(options_.info_log, "Backup %u corrupted -- %s",
backup_iter->first, s.ToString().c_str());
corrupt_backups_.insert(
std::make_pair(backup_iter->first,
std::make_pair(s, std::move(backup_iter->second))));
} else if (!s.ok()) {
// Distinguish corruption errors from errors in the backup Env.
// Errors in the backup Env (i.e., this code path) will cause Open() to
// fail, whereas corruption errors would not cause Open() failures.
return s;
} else {
ROCKS_LOG_INFO(options_.info_log, "Loading backup %" PRIu32 " OK:\n%s",
backup_iter->first,
backup_iter->second->GetInfoString().c_str());
assert(latest_valid_backup_id_ == 0 ||
latest_valid_backup_id_ > backup_iter->first);
if (latest_valid_backup_id_ == 0) {
latest_valid_backup_id_ = backup_iter->first;
}
--valid_backups_to_open;
}
}
for (const auto& corrupt : corrupt_backups_) {
backups_.erase(backups_.find(corrupt.first));
}
// erase the backups before max_valid_backups_to_open
int num_unopened_backups;
if (options_.max_valid_backups_to_open == 0) {
num_unopened_backups = 0;
} else {
num_unopened_backups =
std::max(0, static_cast<int>(backups_.size()) -
options_.max_valid_backups_to_open);
}
for (int i = 0; i < num_unopened_backups; ++i) {
assert(backups_.begin()->second->Empty());
backups_.erase(backups_.begin());
}
}
ROCKS_LOG_INFO(options_.info_log, "Latest backup is %u", latest_backup_id_);
ROCKS_LOG_INFO(options_.info_log, "Latest valid backup is %u",
latest_valid_backup_id_);
// set up threads perform copies from files_to_copy_or_create_ in the
// background
for (int t = 0; t < options_.max_background_operations; t++) {
threads_.emplace_back([this]() {
#if defined(_GNU_SOURCE) && defined(__GLIBC_PREREQ)
#if __GLIBC_PREREQ(2, 12)
pthread_setname_np(pthread_self(), "backup_engine");
#endif
#endif
CopyOrCreateWorkItem work_item;
while (files_to_copy_or_create_.read(work_item)) {
CopyOrCreateResult result;
result.status = CopyOrCreateFile(
work_item.src_path, work_item.dst_path, work_item.contents,
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.progress_callback);
work_item.result.set_value(std::move(result));
}
});
}
ROCKS_LOG_INFO(options_.info_log, "Initialized BackupEngine");
return Status::OK();
}
Status BackupEngineImpl::CreateNewBackupWithMetadata(
DB* db, const std::string& app_metadata, bool flush_before_backup,
std::function<void()> progress_callback) {
assert(initialized_);
assert(!read_only_);
if (app_metadata.size() > kMaxAppMetaSize) {
return Status::InvalidArgument("App metadata too large");
}
BackupID new_backup_id = latest_backup_id_ + 1;
assert(backups_.find(new_backup_id) == backups_.end());
auto private_dir = GetAbsolutePath(GetPrivateFileRel(new_backup_id));
Status s = backup_env_->FileExists(private_dir);
if (s.ok()) {
// maybe last backup failed and left partial state behind, clean it up.
// need to do this before updating backups_ such that a private dir
// named after new_backup_id will be cleaned up
s = GarbageCollect();
} else if (s.IsNotFound()) {
// normal case, the new backup's private dir doesn't exist yet
s = Status::OK();
}
auto ret = backups_.insert(std::make_pair(
new_backup_id, unique_ptr<BackupMeta>(new BackupMeta(
GetBackupMetaFile(new_backup_id, false /* tmp */),
GetBackupMetaFile(new_backup_id, true /* tmp */),
&backuped_file_infos_, backup_env_))));
assert(ret.second == true);
auto& new_backup = ret.first->second;
new_backup->RecordTimestamp();
new_backup->SetAppMetadata(app_metadata);
auto start_backup = backup_env_->NowMicros();
ROCKS_LOG_INFO(options_.info_log,
"Started the backup process -- creating backup %u",
new_backup_id);
if (s.ok()) {
s = backup_env_->CreateDir(private_dir);
}
RateLimiter* rate_limiter = options_.backup_rate_limiter.get();
if (rate_limiter) {
copy_file_buffer_size_ = rate_limiter->GetSingleBurstBytes();
}
// 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;
std::vector<BackupAfterCopyOrCreateWorkItem> backup_items_to_finish;
// Add a CopyOrCreateWorkItem to the channel for each live file
db->DisableFileDeletions();
if (s.ok()) {
CheckpointImpl checkpoint(db);
uint64_t sequence_number = 0;
s = checkpoint.CreateCustomCheckpoint(
db->GetDBOptions(),
[&](const std::string& /*src_dirname*/, const std::string& /*fname*/,
FileType) {
// custom checkpoint will switch to calling copy_file_cb after it sees
// NotSupported returned from link_file_cb.
return Status::NotSupported();
} /* link_file_cb */,
[&](const std::string& src_dirname, const std::string& fname,
uint64_t size_limit_bytes, FileType type) {
if (type == kLogFile && !options_.backup_log_files) {
return Status::OK();
}
Log(options_.info_log, "add file for backup %s", fname.c_str());
uint64_t size_bytes = 0;
Status st;
if (type == kTableFile) {
st = db_env_->GetFileSize(src_dirname + fname, &size_bytes);
}
if (st.ok()) {
st = AddBackupFileWorkItem(
live_dst_paths, backup_items_to_finish, new_backup_id,
options_.share_table_files && type == kTableFile, src_dirname,
fname, rate_limiter, size_bytes, size_limit_bytes,
options_.share_files_with_checksum && type == kTableFile,
progress_callback);
}
return st;
} /* copy_file_cb */,
[&](const std::string& fname, const std::string& contents, FileType) {
Log(options_.info_log, "add file for backup %s", fname.c_str());
return AddBackupFileWorkItem(
live_dst_paths, backup_items_to_finish, new_backup_id,
false /* shared */, "" /* src_dir */, fname, rate_limiter,
contents.size(), 0 /* size_limit */, false /* shared_checksum */,
progress_callback, contents);
} /* create_file_cb */,
&sequence_number, flush_before_backup ? 0 : port::kMaxUint64);
if (s.ok()) {
new_backup->SetSequenceNumber(sequence_number);
}
}
ROCKS_LOG_INFO(options_.info_log, "add files for backup done, wait finish.");
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);
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() && 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
ROCKS_LOG_INFO(options_.info_log, "Backup failed -- %s",
s.ToString().c_str());
ROCKS_LOG_INFO(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;
latest_valid_backup_id_ = new_backup_id;
ROCKS_LOG_INFO(options_.info_log, "Backup DONE. All is good");
// backup_speed is in byte/second
double backup_speed = new_backup->GetSize() / (1.048576 * backup_time);
ROCKS_LOG_INFO(options_.info_log, "Backup number of files: %u",
new_backup->GetNumberFiles());
char human_size[16];
AppendHumanBytes(new_backup->GetSize(), human_size, sizeof(human_size));
ROCKS_LOG_INFO(options_.info_log, "Backup size: %s", human_size);
ROCKS_LOG_INFO(options_.info_log, "Backup time: %" PRIu64 " microseconds",
backup_time);
ROCKS_LOG_INFO(options_.info_log, "Backup speed: %.3f MB/s", backup_speed);
ROCKS_LOG_INFO(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_);
ROCKS_LOG_INFO(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_);
ROCKS_LOG_INFO(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);
}
if (options_.max_valid_backups_to_open == port::kMaxInt32) {
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));
ROCKS_LOG_INFO(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);
}
} else {
ROCKS_LOG_WARN(
options_.info_log,
"DeleteBackup cleanup is limited since `max_valid_backups_to_open` "
"constrains how many backups the engine knows about");
}
// 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));
ROCKS_LOG_INFO(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(), backup.second->GetAppMetadata()));
}
}
}
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_);
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");
}
ROCKS_LOG_INFO(options_.info_log, "Restoring backup id %u\n", backup_id);
ROCKS_LOG_INFO(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) {
ROCKS_LOG_INFO(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);
}
RateLimiter* rate_limiter = options_.restore_rate_limiter.get();
if (rate_limiter) {
copy_file_buffer_size_ = rate_limiter->GetSingleBurstBytes();
}
Status s;
std::vector<RestoreAfterCopyOrCreateWorkItem> 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;
ROCKS_LOG_INFO(options_.info_log, "Restoring %s to %s\n", file.c_str(),
dst.c_str());
CopyOrCreateWorkItem copy_or_create_work_item(
GetAbsolutePath(file), dst, "" /* contents */, backup_env_, db_env_,
false, rate_limiter, 0 /* size_limit */);
RestoreAfterCopyOrCreateWorkItem after_copy_or_create_work_item(
copy_or_create_work_item.result.get_future(),
file_info->checksum_value);
files_to_copy_or_create_.write(std::move(copy_or_create_work_item));
restore_items_to_finish.push_back(
std::move(after_copy_or_create_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;
}
}
ROCKS_LOG_INFO(options_.info_log, "Restoring done -- %s\n",
s.ToString().c_str());
return s;
}
Status BackupEngineImpl::VerifyBackup(BackupID backup_id) {
assert(initialized_);
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();
}
auto& backup = backup_itr->second;
if (backup->Empty()) {
return Status::NotFound();
}
ROCKS_LOG_INFO(options_.info_log, "Verifying backup id %u\n", backup_id);
std::unordered_map<std::string, uint64_t> curr_abs_path_to_size;
for (const auto& rel_dir : {GetPrivateFileRel(backup_id), GetSharedFileRel(),
GetSharedFileWithChecksumRel()}) {
const auto abs_dir = GetAbsolutePath(rel_dir);
InsertPathnameToSizeBytes(abs_dir, backup_env_, &curr_abs_path_to_size);
}
for (const auto& file_info : backup->GetFiles()) {
const auto abs_path = GetAbsolutePath(file_info->filename);
if (curr_abs_path_to_size.find(abs_path) == curr_abs_path_to_size.end()) {
return Status::NotFound("File missing: " + abs_path);
}
if (file_info->size != curr_abs_path_to_size[abs_path]) {
return Status::Corruption("File corrupted: " + abs_path);
}
}
return Status::OK();
}
Status BackupEngineImpl::CopyOrCreateFile(
const std::string& src, const std::string& dst, const std::string& contents,
Env* src_env, Env* dst_env, bool sync, RateLimiter* rate_limiter,
uint64_t* size, uint32_t* checksum_value, uint64_t size_limit,
std::function<void()> progress_callback) {
assert(src.empty() != contents.empty());
Status s;
unique_ptr<WritableFile> dst_file;
unique_ptr<SequentialFile> src_file;
EnvOptions env_options;
env_options.use_mmap_writes = false;
// TODO:(gzh) maybe use direct reads/writes here if possible
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 = dst_env->NewWritableFile(dst, &dst_file, env_options);
if (s.ok() && !src.empty()) {
s = src_env->NewSequentialFile(src, &src_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;
unique_ptr<char[]> buf;
if (!src.empty()) {
src_reader.reset(new SequentialFileReader(std::move(src_file)));
buf.reset(new char[copy_file_buffer_size_]);
}
Slice data;
uint64_t processed_buffer_size = 0;
do {
if (stop_backup_.load(std::memory_order_acquire)) {
return Status::Incomplete("Backup stopped");
}
if (!src.empty()) {
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());
processed_buffer_size += buffer_to_read;
} else {
data = contents;
}
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->Request(data.size(), Env::IO_LOW, nullptr /* stats */,
RateLimiter::OpType::kWrite);
}
if (processed_buffer_size > options_.callback_trigger_interval_size) {
processed_buffer_size -= options_.callback_trigger_interval_size;
std::lock_guard<std::mutex> lock(byte_report_mutex_);
progress_callback();
}
} while (s.ok() && contents.empty() && data.size() > 0 && size_limit > 0);
if (s.ok() && sync) {
s = dest_writer->Sync(false);
}
if (s.ok()) {
s = dest_writer->Close();
}
return s;
}
// fname will always start with "/"
Status BackupEngineImpl::AddBackupFileWorkItem(
std::unordered_set<std::string>& live_dst_paths,
std::vector<BackupAfterCopyOrCreateWorkItem>& backup_items_to_finish,
BackupID backup_id, bool shared, const std::string& src_dir,
const std::string& fname, RateLimiter* rate_limiter, uint64_t size_bytes,
uint64_t size_limit, bool shared_checksum,
std::function<void()> progress_callback, const std::string& contents) {
assert(!fname.empty() && fname[0] == '/');
assert(contents.empty() != src_dir.empty());
std::string dst_relative = fname.substr(1);
std::string dst_relative_tmp;
Status s;
uint32_t checksum_value = 0;
if (shared && shared_checksum) {
// add checksum and file length to the file name
s = CalculateChecksum(src_dir + fname, db_env_, size_limit,
&checksum_value);
if (!s.ok()) {
return s;
}
if (size_bytes == port::kMaxUint64) {
return Status::NotFound("File missing: " + src_dir + fname);
}
dst_relative =
GetSharedFileWithChecksum(dst_relative, checksum_value, size_bytes);
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 = GetPrivateFileRel(backup_id, false, dst_relative);
}
// We copy into `temp_dest_path` and, once finished, rename it to
// `final_dest_path`. This allows files to atomically appear at
// `final_dest_path`. We can copy directly to the final path when atomicity
// is unnecessary, like for files in private backup directories.
const std::string* copy_dest_path;
std::string temp_dest_path;
std::string final_dest_path = GetAbsolutePath(dst_relative);
if (!dst_relative_tmp.empty()) {
temp_dest_path = GetAbsolutePath(dst_relative_tmp);
copy_dest_path = &temp_dest_path;
} else {
copy_dest_path = &final_dest_path;
}
// 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 final_dest_path is the same path as another live file
const bool same_path =
live_dst_paths.find(final_dest_path) != live_dst_paths.end();
bool file_exists = false;
if (shared && !same_path) {
Status exist = backup_env_->FileExists(final_dest_path);
if (exist.ok()) {
file_exists = true;
} else if (exist.IsNotFound()) {
file_exists = false;
} else {
assert(s.IsIOError());
return exist;
}
}
if (!contents.empty()) {
need_to_copy = false;
} else if (shared && (same_path || file_exists)) {
need_to_copy = false;
if (shared_checksum) {
ROCKS_LOG_INFO(options_.info_log,
"%s already present, with checksum %u and size %" PRIu64,
fname.c_str(), checksum_value, size_bytes);
} 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
ROCKS_LOG_INFO(
options_.info_log,
"%s already present, but not referenced by any backup. We will "
"overwrite the file.",
fname.c_str());
need_to_copy = true;
backup_env_->DeleteFile(final_dest_path);
} else {
// the file is present and referenced by a backup
ROCKS_LOG_INFO(options_.info_log,
"%s already present, calculate checksum", fname.c_str());
s = CalculateChecksum(src_dir + fname, db_env_, size_limit,
&checksum_value);
}
}
live_dst_paths.insert(final_dest_path);
if (!contents.empty() || need_to_copy) {
ROCKS_LOG_INFO(options_.info_log, "Copying %s to %s", fname.c_str(),
copy_dest_path->c_str());
CopyOrCreateWorkItem copy_or_create_work_item(
src_dir.empty() ? "" : src_dir + fname, *copy_dest_path, contents,
db_env_, backup_env_, options_.sync, rate_limiter, size_limit,
progress_callback);
BackupAfterCopyOrCreateWorkItem after_copy_or_create_work_item(
copy_or_create_work_item.result.get_future(), shared, need_to_copy,
backup_env_, temp_dest_path, final_dest_path, dst_relative);
files_to_copy_or_create_.write(std::move(copy_or_create_work_item));
backup_items_to_finish.push_back(std::move(after_copy_or_create_work_item));
} else {
std::promise<CopyOrCreateResult> promise_result;
BackupAfterCopyOrCreateWorkItem after_copy_or_create_work_item(
promise_result.get_future(), shared, need_to_copy, backup_env_,
temp_dest_path, final_dest_path, dst_relative);
backup_items_to_finish.push_back(std::move(after_copy_or_create_work_item));
CopyOrCreateResult result;
result.status = s;
result.size = size_bytes;
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_direct_reads = 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::InsertPathnameToSizeBytes(
const std::string& dir, Env* env,
std::unordered_map<std::string, uint64_t>* result) {
assert(result != nullptr);
std::vector<Env::FileAttributes> files_attrs;
Status status = env->FileExists(dir);
if (status.ok()) {
status = env->GetChildrenFileAttributes(dir, &files_attrs);
} else if (status.IsNotFound()) {
// Insert no entries can be considered success
status = Status::OK();
}
const bool slash_needed = dir.empty() || dir.back() != '/';
for (const auto& file_attrs : files_attrs) {
result->emplace(dir + (slash_needed ? "/" : "") + file_attrs.name,
file_attrs.size_bytes);
}
return status;
}
Status BackupEngineImpl::GarbageCollect() {
assert(!read_only_);
ROCKS_LOG_INFO(options_.info_log, "Starting garbage collection");
if (options_.max_valid_backups_to_open == port::kMaxInt32) {
ROCKS_LOG_WARN(
options_.info_log,
"Garbage collection is limited since `max_valid_backups_to_open` "
"constrains how many backups the engine knows about");
}
if (options_.share_table_files &&
options_.max_valid_backups_to_open == port::kMaxInt32) {
// delete obsolete shared files
// we cannot do this when BackupEngine has `max_valid_backups_to_open` set
// as those engines don't know about all shared files.
std::vector<std::string> shared_children;
{
std::string shared_path;
if (options_.share_files_with_checksum) {
shared_path = GetAbsolutePath(GetSharedFileWithChecksumRel());
} else {
shared_path = GetAbsolutePath(GetSharedFileRel());
}
auto s = backup_env_->FileExists(shared_path);
if (s.ok()) {
s = backup_env_->GetChildren(shared_path, &shared_children);
} else if (s.IsNotFound()) {
s = Status::OK();
}
if (!s.ok()) {
return s;
}
}
for (auto& child : shared_children) {
std::string rel_fname;
if (options_.share_files_with_checksum) {
rel_fname = GetSharedFileWithChecksumRel(child);
} else {
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));
ROCKS_LOG_INFO(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) {
// it's ok to do this when BackupEngine has `max_valid_backups_to_open` set
// as the engine always knows all valid backup numbers.
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));
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);
ROCKS_LOG_INFO(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);
ROCKS_LOG_INFO(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;
}
Slice kMetaDataPrefix("metadata ");
// each backup meta file is of the format:
// <timestamp>
// <seq number>
// <metadata(literal string)> <metadata> (optional)
// <number of files>
// <file1> <crc32(literal string)> <crc32_value>
// <file2> <crc32(literal string)> <crc32_value>
// ...
Status BackupEngineImpl::BackupMeta::LoadFromFile(
const std::string& backup_dir,
const std::unordered_map<std::string, uint64_t>& abs_path_to_size) {
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'
if (data.starts_with(kMetaDataPrefix)) {
// app metadata present
data.remove_prefix(kMetaDataPrefix.size());
Slice hex_encoded_metadata = GetSliceUntil(&data, '\n');
bool decode_success = hex_encoded_metadata.DecodeHex(&app_metadata_);
if (!decode_success) {
return Status::Corruption(
"Failed to decode stored hex encoded app metadata");
}
}
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 {
std::string abs_path = backup_dir + "/" + filename;
try {
size = abs_path_to_size.at(abs_path);
} catch (std::out_of_range&) {
return Status::Corruption("Size missing for pathname: " + abs_path);
}
}
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;
env_options.use_direct_writes = false;
s = env_->NewWritableFile(meta_tmp_filename_, &backup_meta_file, env_options);
if (!s.ok()) {
return s;
}
unique_ptr<char[]> buf(new char[max_backup_meta_file_size_]);
size_t 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_);
if (!app_metadata_.empty()) {
std::string hex_encoded_metadata =
Slice(app_metadata_).ToString(/* hex */ true);
// +1 to accomodate newline character
size_t hex_meta_strlen = kMetaDataPrefix.ToString().length() + hex_encoded_metadata.length() + 1;
if (hex_meta_strlen >= buf_size) {
return Status::Corruption("Buffer too small to fit backup metadata");
}
else if (len + hex_meta_strlen >= buf_size) {
backup_meta_file->Append(Slice(buf.get(), len));
buf.reset();
unique_ptr<char[]> new_reset_buf(new char[max_backup_meta_file_size_]);
buf.swap(new_reset_buf);
len = 0;
}
len += snprintf(buf.get() + len, buf_size - len, "%s%s\n",
kMetaDataPrefix.ToString().c_str(),
hex_encoded_metadata.c_str());
}
char writelen_temp[19];
if (len + snprintf(writelen_temp, sizeof(writelen_temp),
"%" ROCKSDB_PRIszt "\n", files_.size()) >= buf_size) {
backup_meta_file->Append(Slice(buf.get(), len));
buf.reset();
unique_ptr<char[]> new_reset_buf(new char[max_backup_meta_file_size_]);
buf.swap(new_reset_buf);
len = 0;
}
{
const char *const_write = writelen_temp;
len += snprintf(buf.get() + len, buf_size - len, "%s", const_write);
}
for (const auto& file : files_) {
// use crc32 for now, switch to something else if needed
size_t newlen = len + file->filename.length() + snprintf(writelen_temp,
sizeof(writelen_temp), " crc32 %u\n", file->checksum_value);
const char *const_write = writelen_temp;
if (newlen >= buf_size) {
backup_meta_file->Append(Slice(buf.get(), len));
buf.reset();
unique_ptr<char[]> new_reset_buf(new char[max_backup_meta_file_size_]);
buf.swap(new_reset_buf);
len = 0;
}
len += snprintf(buf.get() + len, buf_size - len, "%s%s",
file->filename.c_str(), const_write);
}
s = backup_meta_file->Append(Slice(buf.get(), 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_tmp_filename_, 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() {}
// The returned BackupInfos are in chronological order, which means the
// latest backup comes last.
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);
}
virtual Status VerifyBackup(BackupID backup_id) override {
return backup_engine_->VerifyBackup(backup_id);
}
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();
}
} // namespace rocksdb
#endif // ROCKSDB_LITE
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