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rocksdb/utilities/backupable/backupable_db.cc

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[RocksDB] BackupableDB Summary: In this diff I present you BackupableDB v1. You can easily use it to backup your DB and it will do incremental snapshots for you. Let's first describe how you would use BackupableDB. It's inheriting StackableDB interface so you can easily construct it with your DB object -- it will add a method RollTheSnapshot() to the DB object. When you call RollTheSnapshot(), current snapshot of the DB will be stored in the backup dir. To restore, you can just call RestoreDBFromBackup() on a BackupableDB (which is a static method) and it will restore all files from the backup dir. In the next version, it will even support automatic backuping every X minutes. There are multiple things you can configure: 1. backup_env and db_env can be different, which is awesome because then you can easily backup to HDFS or wherever you feel like. 2. sync - if true, it *guarantees* backup consistency on machine reboot 3. number of snapshots to keep - this will keep last N snapshots around if you want, for some reason, be able to restore from an earlier snapshot. All the backuping is done in incremental fashion - if we already have 00010.sst, we will not copy it again. *IMPORTANT* -- This is based on assumption that 00010.sst never changes - two files named 00010.sst from the same DB will always be exactly the same. Is this true? I always copy manifest, current and log files. 4. You can decide if you want to flush the memtables before you backup, or you're fine with backing up the log files -- either way, you get a complete and consistent view of the database at a time of backup. 5. More things you can find in BackupableDBOptions Here is the directory structure I use: backup_dir/CURRENT_SNAPSHOT - just 4 bytes holding the latest snapshot 0, 1, 2, ... - files containing serialized version of each snapshot - containing a list of files files/*.sst - sst files shared between snapshots - if one snapshot references 00010.sst and another one needs to backup it from the DB, it will just reference the same file files/ 0/, 1/, 2/, ... - snapshot directories containing private snapshot files - current, manifest and log files All the files are ref counted and deleted immediatelly when they get out of scope. Some other stuff in this diff: 1. Added GetEnv() method to the DB. Discussed with @haobo and we agreed that it seems right thing to do. 2. Fixed StackableDB interface. The way it was set up before, I was not able to implement BackupableDB. Test Plan: I have a unittest, but please don't look at this yet. I just hacked it up to help me with debugging. I will write a lot of good tests and update the diff. Also, `make asan_check` Reviewers: dhruba, haobo, emayanke Reviewed By: dhruba CC: leveldb, haobo Differential Revision: https://reviews.facebook.net/D14295
11 years ago
// 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.
#include "utilities/backupable_db.h"
#include "db/filename.h"
#include "util/coding.h"
#include "rocksdb/transaction_log.h"
#define __STDC_FORMAT_MACROS
#include <inttypes.h>
#include <algorithm>
#include <vector>
#include <map>
#include <string>
#include <limits>
namespace rocksdb {
// -------- BackupEngine class ---------
class BackupEngine {
public:
BackupEngine(Env* db_env, const BackupableDBOptions& options);
~BackupEngine();
Status CreateNewBackup(DB* db, bool flush_before_backup = false);
Status PurgeOldBackups(uint32_t num_backups_to_keep);
Status DeleteBackup(BackupID backup_id);
void GetBackupInfo(std::vector<BackupInfo>* backup_info);
Status RestoreDBFromBackup(BackupID backup_id, const std::string &db_dir,
const std::string &wal_dir);
Status RestoreDBFromLatestBackup(const std::string &db_dir,
const std::string &wal_dir) {
return RestoreDBFromBackup(latest_backup_id_, db_dir, wal_dir);
}
private:
class BackupMeta {
public:
BackupMeta(const std::string& meta_filename,
std::unordered_map<std::string, int>* file_refs, Env* env)
: timestamp_(0), size_(0), meta_filename_(meta_filename),
file_refs_(file_refs), env_(env) {}
~BackupMeta() {}
void RecordTimestamp() {
env_->GetCurrentTime(&timestamp_);
}
int64_t GetTimestamp() const {
return timestamp_;
}
uint64_t GetSize() const {
return size_;
}
void AddFile(const std::string& filename, uint64_t size);
void Delete();
bool Empty() {
return files_.empty();
}
const std::vector<std::string>& GetFiles() {
return files_;
}
Status LoadFromFile(const std::string& backup_dir);
Status StoreToFile(bool sync);
private:
int64_t timestamp_;
uint64_t size_;
std::string const meta_filename_;
// files with relative paths (without "/" prefix!!)
std::vector<std::string> files_;
std::unordered_map<std::string, int>* file_refs_;
Env* env_;
}; // 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 GetPrivateFileRel(BackupID backup_id,
const std::string &file = "") const {
assert(file.size() == 0 || file[0] != '/');
return GetPrivateDirRel() + "/" + std::to_string(backup_id) + "/" + file;
}
inline std::string GetSharedFileRel(const std::string& file = "") const {
assert(file.size() == 0 || file[0] != '/');
return "shared/" + file;
}
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() + "/" + std::to_string(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,
uint64_t* size = nullptr,
uint64_t size_limit = 0);
// if size_limit == 0, there is no size limit, copy everything
Status BackupFile(BackupID backup_id,
BackupMeta* backup,
bool shared,
const std::string& src_dir,
const std::string& src_fname, // starts with "/"
uint64_t size_limit = 0);
// Will delete all the files we don't need anymore
// If full_scan == true, it will do the full scan of files/ directory
// and delete all the files that are not referenced from backuped_file_refs_
void GarbageCollection(bool full_scan);
// backup state data
BackupID latest_backup_id_;
std::map<BackupID, BackupMeta> backups_;
std::unordered_map<std::string, int> backuped_file_refs_;
std::vector<BackupID> obsolete_backups_;
// options data
BackupableDBOptions options_;
Env* db_env_;
Env* backup_env_;
// constants
static const size_t max_backup_meta_file_size_ = 10 * 1024 * 1024; // 10MB
static const size_t copy_file_buffer_size_ = 5 * 1024 * 1024LL; // 5MB
};
BackupEngine::BackupEngine(Env* db_env, const BackupableDBOptions& options)
: options_(options),
db_env_(db_env),
backup_env_(options.backup_env != nullptr ? options.backup_env : db_env_) {
// create all the dirs we need
backup_env_->CreateDirIfMissing(GetAbsolutePath());
backup_env_->CreateDirIfMissing(GetAbsolutePath(GetSharedFileRel()));
backup_env_->CreateDirIfMissing(GetAbsolutePath(GetPrivateDirRel()));
backup_env_->CreateDirIfMissing(GetBackupMetaDir());
std::vector<std::string> backup_meta_files;
backup_env_->GetChildren(GetBackupMetaDir(), &backup_meta_files);
// create backups_ structure
for (auto& file : backup_meta_files) {
BackupID backup_id = 0;
sscanf(file.c_str(), "%u", &backup_id);
if (backup_id == 0 || file != std::to_string(backup_id)) {
// invalid file name, delete that
backup_env_->DeleteFile(GetBackupMetaDir() + "/" + file);
continue;
}
assert(backups_.find(backup_id) == backups_.end());
backups_.insert(std::make_pair(
backup_id, BackupMeta(GetBackupMetaFile(backup_id),
&backuped_file_refs_, backup_env_)));
}
if (options_.destroy_old_data) { // Destory old data
for (auto& backup : backups_) {
backup.second.Delete();
obsolete_backups_.push_back(backup.first);
}
backups_.clear();
// start from beginning
latest_backup_id_ = 0;
// GarbageCollection() will do the actual deletion
} 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 - deleting -- %s",
backup.first, s.ToString().c_str());
backup.second.Delete();
obsolete_backups_.push_back(backup.first);
}
}
// delete obsolete backups from the structure
for (auto ob : obsolete_backups_) {
backups_.erase(ob);
}
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;
}
}
// delete any backups that claim to be later than latest
for (auto itr = backups_.upper_bound(latest_backup_id_);
itr != backups_.end();) {
itr->second.Delete();
obsolete_backups_.push_back(itr->first);
itr = backups_.erase(itr);
}
PutLatestBackupFileContents(latest_backup_id_); // Ignore errors
GarbageCollection(true);
Log(options_.info_log,
"Initialized BackupEngine, the latest backup is %u.",
latest_backup_id_);
}
BackupEngine::~BackupEngine() {
LogFlush(options_.info_log);
}
Status BackupEngine::CreateNewBackup(DB* db, bool flush_before_backup) {
Status s;
std::vector<std::string> live_files;
VectorLogPtr live_wal_files;
uint64_t manifest_file_size = 0;
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) {
// returns file names prefixed with "/"
s = db->GetSortedWalFiles(live_wal_files);
}
if (!s.ok()) {
db->EnableFileDeletions();
return s;
}
BackupID new_backup_id = latest_backup_id_ + 1;
assert(backups_.find(new_backup_id) == backups_.end());
auto ret = backups_.insert(std::make_pair(
new_backup_id, BackupMeta(GetBackupMetaFile(new_backup_id),
&backuped_file_refs_, backup_env_)));
assert(ret.second == true);
auto& new_backup = ret.first->second;
new_backup.RecordTimestamp();
Log(options_.info_log, "Started the backup process -- creating backup %u",
new_backup_id);
// create private dir
s = backup_env_->CreateDir(GetAbsolutePath(GetPrivateFileRel(new_backup_id)));
// copy live_files
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");
}
[RocksDB] BackupableDB Summary: In this diff I present you BackupableDB v1. You can easily use it to backup your DB and it will do incremental snapshots for you. Let's first describe how you would use BackupableDB. It's inheriting StackableDB interface so you can easily construct it with your DB object -- it will add a method RollTheSnapshot() to the DB object. When you call RollTheSnapshot(), current snapshot of the DB will be stored in the backup dir. To restore, you can just call RestoreDBFromBackup() on a BackupableDB (which is a static method) and it will restore all files from the backup dir. In the next version, it will even support automatic backuping every X minutes. There are multiple things you can configure: 1. backup_env and db_env can be different, which is awesome because then you can easily backup to HDFS or wherever you feel like. 2. sync - if true, it *guarantees* backup consistency on machine reboot 3. number of snapshots to keep - this will keep last N snapshots around if you want, for some reason, be able to restore from an earlier snapshot. All the backuping is done in incremental fashion - if we already have 00010.sst, we will not copy it again. *IMPORTANT* -- This is based on assumption that 00010.sst never changes - two files named 00010.sst from the same DB will always be exactly the same. Is this true? I always copy manifest, current and log files. 4. You can decide if you want to flush the memtables before you backup, or you're fine with backing up the log files -- either way, you get a complete and consistent view of the database at a time of backup. 5. More things you can find in BackupableDBOptions Here is the directory structure I use: backup_dir/CURRENT_SNAPSHOT - just 4 bytes holding the latest snapshot 0, 1, 2, ... - files containing serialized version of each snapshot - containing a list of files files/*.sst - sst files shared between snapshots - if one snapshot references 00010.sst and another one needs to backup it from the DB, it will just reference the same file files/ 0/, 1/, 2/, ... - snapshot directories containing private snapshot files - current, manifest and log files All the files are ref counted and deleted immediatelly when they get out of scope. Some other stuff in this diff: 1. Added GetEnv() method to the DB. Discussed with @haobo and we agreed that it seems right thing to do. 2. Fixed StackableDB interface. The way it was set up before, I was not able to implement BackupableDB. Test Plan: I have a unittest, but please don't look at this yet. I just hacked it up to help me with debugging. I will write a lot of good tests and update the diff. Also, `make asan_check` Reviewers: dhruba, haobo, emayanke Reviewed By: dhruba CC: leveldb, haobo Differential Revision: https://reviews.facebook.net/D14295
11 years ago
// we should only get sst, manifest and current files here
assert(type == kTableFile ||
type == kDescriptorFile ||
type == kCurrentFile);
// rules:
// * if it's kTableFile, than it's shared
// * if it's kDescriptorFile, limit the size to manifest_file_size
s = BackupFile(new_backup_id,
&new_backup,
type == kTableFile, /* shared */
db->GetName(), /* src_dir */
live_files[i], /* src_fname */
(type == kDescriptorFile) ? manifest_file_size : 0);
}
// copy WAL files
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 = BackupFile(new_backup_id,
&new_backup,
false, /* not shared */
db->GetOptions().wal_dir,
live_wal_files[i]->PathName());
}
}
// we copied all the files, enable file deletions
db->EnableFileDeletions();
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()) {
// clean all the files we might have created
Log(options_.info_log, "Backup failed -- %s", s.ToString().c_str());
backups_.erase(new_backup_id);
GarbageCollection(true);
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");
return s;
}
Status BackupEngine::PurgeOldBackups(uint32_t num_backups_to_keep) {
Log(options_.info_log, "Purging old backups, keeping %u",
num_backups_to_keep);
while (num_backups_to_keep < backups_.size()) {
Log(options_.info_log, "Deleting backup %u", backups_.begin()->first);
backups_.begin()->second.Delete();
obsolete_backups_.push_back(backups_.begin()->first);
backups_.erase(backups_.begin());
}
GarbageCollection(false);
return Status::OK();
}
Status BackupEngine::DeleteBackup(BackupID backup_id) {
Log(options_.info_log, "Deleting backup %u", backup_id);
auto backup = backups_.find(backup_id);
if (backup == backups_.end()) {
return Status::NotFound("Backup not found");
}
backup->second.Delete();
obsolete_backups_.push_back(backup_id);
backups_.erase(backup);
GarbageCollection(false);
return Status::OK();
}
void BackupEngine::GetBackupInfo(std::vector<BackupInfo>* backup_info) {
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()));
}
}
}
Status BackupEngine::RestoreDBFromBackup(BackupID backup_id,
const std::string &db_dir,
const std::string &wal_dir) {
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);
// just in case. Ignore errors
db_env_->CreateDirIfMissing(db_dir);
db_env_->CreateDirIfMissing(wal_dir);
// delete log files that might have been already in wal_dir.
// This is important since they might get replayed to the restored DB,
// which will then differ from the backuped DB
std::vector<std::string> wal_dir_children;
db_env_->GetChildren(wal_dir, &wal_dir_children); // ignore errors
for (auto f : wal_dir_children) {
db_env_->DeleteFile(wal_dir + "/" + f); // ignore errors
}
Status s;
for (auto& file : backup.GetFiles()) {
std::string dst;
// 1. extract the filename
size_t slash = file.find_last_of('/');
// file will either be shared/<file> or private/<number>/<file>
assert(slash != std::string::npos);
dst = file.substr(slash + 1);
// 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());
s = CopyFile(GetAbsolutePath(file), dst, backup_env_, db_env_, false);
if (!s.ok()) {
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 BackupEngine::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 = new char[10];
Slice data(buf, 0);
s = file->Read(10, &data, buf);
if (!s.ok() || data.size() == 0) {
delete[] buf;
return s.ok() ? Status::Corruption("Latest backup file corrupted") : s;
}
sscanf(data.data(), "%u", latest_backup);
if (backup_env_->FileExists(GetBackupMetaFile(*latest_backup)) == false) {
s = Status::Corruption("Latest backup file corrupted");
}
delete[] buf;
return Status::OK();
}
// this operation HAS to be atomic
// writing 4 bytes to the file is atomic alright, but we should *never*
// do something like 1. delete file, 2. write new file
// We write to a tmp file and then atomically rename
Status BackupEngine::PutLatestBackupFileContents(uint32_t latest_backup) {
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;
}
char* file_contents = new char[10];
int len = sprintf(file_contents, "%u\n", latest_backup);
s = file->Append(Slice(file_contents, len));
if (s.ok() && options_.sync) {
file->Sync();
}
if (s.ok()) {
s = file->Close();
}
if (s.ok()) {
// atomically replace real file with new tmp
s = backup_env_->RenameFile(GetLatestBackupFile(true),
GetLatestBackupFile(false));
}
return s;
}
Status BackupEngine::CopyFile(const std::string& src,
const std::string& dst,
Env* src_env,
Env* dst_env,
bool sync,
uint64_t* size,
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;
if (size != nullptr) {
*size = 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;
}
char* buf = new char[copy_file_buffer_size_];
Slice data(buf, 0);
do {
size_t buffer_to_read = (copy_file_buffer_size_ < size_limit) ?
copy_file_buffer_size_ : size_limit;
s = src_file->Read(buffer_to_read, &data, buf);
size_limit -= data.size();
if (size != nullptr) {
*size += data.size();
}
if (s.ok()) {
s = dst_file->Append(data);
}
} while (s.ok() && data.size() > 0 && size_limit > 0);
if (s.ok() && sync) {
s = dst_file->Sync();
}
return s;
}
// src_fname will always start with "/"
Status BackupEngine::BackupFile(BackupID backup_id,
BackupMeta* backup,
bool shared,
const std::string& src_dir,
const std::string& src_fname,
uint64_t size_limit) {
assert(src_fname.size() > 0 && src_fname[0] == '/');
std::string dst_relative = src_fname.substr(1);
if (shared) {
dst_relative = GetSharedFileRel(dst_relative);
} else {
dst_relative = GetPrivateFileRel(backup_id, dst_relative);
}
std::string dst_path = GetAbsolutePath(dst_relative);
Status s;
uint64_t size;
// if it's shared, we also need to check if it exists -- if it does,
// no need to copy it again
if (shared && backup_env_->FileExists(dst_path)) {
backup_env_->GetFileSize(dst_path, &size); // Ignore error
Log(options_.info_log, "%s already present", src_fname.c_str());
} else {
Log(options_.info_log, "Copying %s", src_fname.c_str());
s = CopyFile(src_dir + src_fname,
dst_path,
db_env_,
backup_env_,
options_.sync,
&size,
size_limit);
}
if (s.ok()) {
backup->AddFile(dst_relative, size);
}
return s;
}
void BackupEngine::GarbageCollection(bool full_scan) {
Log(options_.info_log, "Starting garbage collection");
std::vector<std::string> to_delete;
for (auto& itr : backuped_file_refs_) {
if (itr.second == 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_refs_.erase(td);
}
if (!full_scan) {
// take care of private dirs -- if full_scan == true, then full_scan will
// take care of them
for (auto backup_id : obsolete_backups_) {
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());
}
obsolete_backups_.clear();
}
if (full_scan) {
Log(options_.info_log, "Starting full scan garbage collection");
// delete obsolete shared files
std::vector<std::string> shared_children;
backup_env_->GetChildren(GetAbsolutePath(GetSharedFileRel()),
&shared_children);
for (auto& child : shared_children) {
std::string rel_fname = GetSharedFileRel(child);
// if it's not refcounted, delete it
if (backuped_file_refs_.find(rel_fname) == backuped_file_refs_.end()) {
// 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));
if (s.ok()) {
Log(options_.info_log, "Deleted %s", rel_fname.c_str());
}
}
}
// delete obsolete private files
std::vector<std::string> private_children;
backup_env_->GetChildren(GetAbsolutePath(GetPrivateDirRel()),
&private_children);
for (auto& child : private_children) {
BackupID backup_id = 0;
sscanf(child.c_str(), "%u", &backup_id);
if (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);
if (s.ok()) {
Log(options_.info_log, "Deleted %s",
(full_private_path + subchild).c_str());
}
}
// finally delete the private dir
Status s = backup_env_->DeleteDir(full_private_path);
Log(options_.info_log, "Deleted dir %s -- %s", full_private_path.c_str(),
s.ToString().c_str());
}
}
}
// ------- BackupMeta class --------
void BackupEngine::BackupMeta::AddFile(const std::string& filename,
uint64_t size) {
size_ += size;
files_.push_back(filename);
auto itr = file_refs_->find(filename);
if (itr == file_refs_->end()) {
file_refs_->insert(std::make_pair(filename, 1));
} else {
++itr->second; // increase refcount if already present
}
}
void BackupEngine::BackupMeta::Delete() {
for (auto& file : files_) {
auto itr = file_refs_->find(file);
assert(itr != file_refs_->end());
--(itr->second); // decrease refcount
}
files_.clear();
// delete meta file
env_->DeleteFile(meta_filename_);
timestamp_ = 0;
}
// each backup meta file is of the format:
// <timestamp>
// <number of files>
// <file1>
// <file2>
// ...
// TODO: maybe add checksum?
Status BackupEngine::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;
}
char* buf = new char[max_backup_meta_file_size_ + 1];
Slice data(buf, 0);
s = backup_meta_file->Read(max_backup_meta_file_size_, &data, buf);
if (!s.ok() || data.size() == max_backup_meta_file_size_) {
delete[] buf;
return s.ok() ? Status::IOError("File size too big") : s;
}
buf[data.size()] = 0;
uint32_t num_files = 0;
int bytes_read = 0;
sscanf(data.data(), "%ld%n", &timestamp_, &bytes_read);
data.remove_prefix(bytes_read + 1); // +1 for '\n'
sscanf(data.data(), "%u%n", &num_files, &bytes_read);
data.remove_prefix(bytes_read + 1); // +1 for '\n'
for (uint32_t i = 0; s.ok() && i < num_files; ++i) {
std::string filename = GetSliceUntil(&data, '\n').ToString();
uint64_t size;
s = env_->GetFileSize(backup_dir + "/" + filename, &size);
AddFile(filename, size);
}
delete[] buf;
return s;
}
Status BackupEngine::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;
}
char* buf = new char[max_backup_meta_file_size_];
int len = 0, buf_size = max_backup_meta_file_size_;
len += snprintf(buf, buf_size, "%" PRId64 "\n", timestamp_);
len += snprintf(buf + len, buf_size - len, "%zu\n", files_.size());
for (size_t i = 0; i < files_.size(); ++i) {
len += snprintf(buf + len, buf_size - len, "%s\n", files_[i].c_str());
}
s = backup_meta_file->Append(Slice(buf, (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;
}
// --- BackupableDB methods --------
BackupableDB::BackupableDB(DB* db, const BackupableDBOptions& options) :
StackableDB(db),
backup_engine_(new BackupEngine(db->GetEnv(), options)) {}
BackupableDB::~BackupableDB() {
delete backup_engine_;
}
Status BackupableDB::CreateNewBackup(bool flush_before_backup) {
return backup_engine_->CreateNewBackup(this, flush_before_backup);
}
void BackupableDB::GetBackupInfo(std::vector<BackupInfo>* backup_info) {
backup_engine_->GetBackupInfo(backup_info);
}
Status BackupableDB::PurgeOldBackups(uint32_t num_backups_to_keep) {
return backup_engine_->PurgeOldBackups(num_backups_to_keep);
}
Status BackupableDB::DeleteBackup(BackupID backup_id) {
return backup_engine_->DeleteBackup(backup_id);
}
// --- RestoreBackupableDB methods ------
RestoreBackupableDB::RestoreBackupableDB(Env* db_env,
const BackupableDBOptions& options)
: backup_engine_(new BackupEngine(db_env, options)) {}
RestoreBackupableDB::~RestoreBackupableDB() {
delete backup_engine_;
}
void
RestoreBackupableDB::GetBackupInfo(std::vector<BackupInfo>* backup_info) {
backup_engine_->GetBackupInfo(backup_info);
}
Status RestoreBackupableDB::RestoreDBFromBackup(BackupID backup_id,
const std::string& db_dir,
const std::string& wal_dir) {
return backup_engine_->RestoreDBFromBackup(backup_id, db_dir, wal_dir);
}
Status
RestoreBackupableDB::RestoreDBFromLatestBackup(const std::string& db_dir,
const std::string& wal_dir) {
return backup_engine_->RestoreDBFromLatestBackup(db_dir, wal_dir);
}
Status RestoreBackupableDB::PurgeOldBackups(uint32_t num_backups_to_keep) {
return backup_engine_->PurgeOldBackups(num_backups_to_keep);
}
Status RestoreBackupableDB::DeleteBackup(BackupID backup_id) {
return backup_engine_->DeleteBackup(backup_id);
}
} // namespace rocksdb