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rocksdb/utilities/backupable/backupable_db.cc
Peter Dillinger 9d8eb77c4d Less I/O for incremental backups, slightly better corruption detection (#7413) 
Summary:
Two relatively simple functional changes to incremental backup
behavior, integrated with a minor refactoring to reduce code redundancy and
improve error/log message. There are nuances to the impact of these changes,
but I believe they are fundamentally good and generally safe. Those functional
changes:

* Incremental backups no longer read DB table files that are already saved to a
shared part of the backup directory, unless `share_files_with_checksum` is used
with `kLegacyCrc32cAndFileSize` naming (discouraged) where crc32c full file
checksums are needed to determine file naming.
  * Justification: incremental backups should not need to read the whole DB,
especially without rate limiting. (Although other BackupEngine reads are not
rate limited either, other non-trivial reads are generally limited by a
corresponding write, as in copying files.) Also, the fact that this is not
already fixed was arguably a bug/oversight in the implementation of https://github.com/facebook/rocksdb/issues/7110.

* When considering whether a table file is already backed up in a shared part
of backup directory, BackupEngine would already query the sizes of source (DB)
and pre-existing destination (backup) files. BackupEngine now uses these file
sizes to detect corruption, as at least one of (a) old backup, (b) backup in
progress, or (c) current DB is corrupt if there's a size mismatch.
  * Justification: a random related fix that also helps to cover a small hole
in corruption checking uncovered by the other functional change:
  * For `share_table_files` without "checksum" (not recommended), the other
change regresses in detecting fundamentally unsafe use of this option
combination: when you might generate different versions of same SST file
number. As demonstrated by `BackupableDBTest.FailOverwritingBackups,` this
regression is greatly mitigated by the new file size checking. Nevertheless,
almost no reason to use `share_files_with_checksum=false` should remain, and
comments are updated appropriately.

Also, this change renames internal function `CalculateChecksum` to
`ReadFileAndComputeChecksum` to make the performance impact of this function
clear in code reviews.

It is not clear what 'same_path' is for in backupable_db.cc, and I suspect it
cannot be true for a DB with unique file names (like DBImpl). Nevertheless,
I've tried to keep its functionality intact when `true` to minimize risk for
now, despite having no unit tests for which it is true.

Select impact details (much more in unit tests): For
`share_files_with_checksum`, I am confident there is no regression (vs.
pre-6.12) in detecting DB or backup corruption at backup creation time, mostly
because the old design did not leverage this extra checksum computation for
detecting inconsistencies at backup creation time. (With computed checksums in
names, a recently corrupted file just looked like a different file vs. what was
already backed up.)

Even in the hypothetical case of DB session id collision (~100 bits entropy
collision), file size in name and/or our file size check add an extra layer of
protection against false success in creating an accurate new backup. (Unit test
included.)

`DB::VerifyChecksum` and `BackupEngine::VerifyBackup` with checksum checking
are still able to catch corruptions that `CreateNewBackup` does not. Note that
when custom file checksum support is added to BackupEngine, that will
essentially give the same power as `DB::VerifyChecksum` into `CreateNewBackup`.
We could add options for `CreateNewBackup` to cover some of what would be
caught by `VerifyBackup` with checksum checking.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7413

Test Plan:
Two new unit tests included, both of which fail without these
changes. Although we don't test the I/O improvement directly, we test it
indirectly in DB corruption detection power that was inadvertently unlocked
with new backup file naming PLUS computing current content checksums (now
removed). (I don't think that case of DB corruption detection justifies reading
the whole DB on incremental backup.)

Reviewed By: zhichao-cao

Differential Revision: D23818480

Pulled By: pdillinger

fbshipit-source-id: 148aff16f001af5b9fd4b22f155311c2461f1bac
2020-09-21 16:19:24 -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 <stdlib.h>
#include <algorithm>
#include <atomic>
#include <cinttypes>
#include <functional>
#include <future>
#include <limits>
#include <map>
#include <mutex>
#include <sstream>
#include <string>
#include <thread>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#include "env/composite_env_wrapper.h"
#include "file/filename.h"
#include "file/sequence_file_reader.h"
#include "file/writable_file_writer.h"
#include "logging/logging.h"
#include "port/port.h"
#include "rocksdb/rate_limiter.h"
#include "rocksdb/transaction_log.h"
#include "table/sst_file_dumper.h"
#include "test_util/sync_point.h"
#include "util/channel.h"
#include "util/coding.h"
#include "util/crc32c.h"
#include "util/string_util.h"
#include "utilities/checkpoint/checkpoint_impl.h"
namespace ROCKSDB_NAMESPACE {
namespace {
using ShareFilesNaming = BackupableDBOptions::ShareFilesNaming;
inline uint32_t ChecksumHexToInt32(const std::string& checksum_hex) {
std::string checksum_str;
Slice(checksum_hex).DecodeHex(&checksum_str);
return EndianSwapValue(DecodeFixed32(checksum_str.c_str()));
}
inline std::string ChecksumStrToHex(const std::string& checksum_str) {
return Slice(checksum_str).ToString(true);
}
inline std::string ChecksumInt32ToHex(const uint32_t& checksum_value) {
std::string checksum_str;
PutFixed32(&checksum_str, EndianSwapValue(checksum_value));
return ChecksumStrToHex(checksum_str);
}
} // namespace
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(const BackupableDBOptions& options, Env* db_env,
bool read_only = false);
~BackupEngineImpl() override;
using BackupEngine::CreateNewBackupWithMetadata;
Status CreateNewBackupWithMetadata(const CreateBackupOptions& options, DB* db,
const std::string& app_metadata) 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;
using BackupEngine::RestoreDBFromBackup;
Status RestoreDBFromBackup(const RestoreOptions& options, BackupID backup_id,
const std::string& db_dir,
const std::string& wal_dir) override;
using BackupEngine::RestoreDBFromLatestBackup;
Status RestoreDBFromLatestBackup(const RestoreOptions& options,
const std::string& db_dir,
const std::string& wal_dir) override {
return RestoreDBFromBackup(options, latest_valid_backup_id_, db_dir,
wal_dir);
}
Status VerifyBackup(BackupID backup_id,
bool verify_with_checksum = false) override;
Status Initialize();
ShareFilesNaming GetNamingNoFlags() const {
return options_.share_files_with_checksum_naming &
BackupableDBOptions::kMaskNoNamingFlags;
}
ShareFilesNaming GetNamingFlags() const {
return options_.share_files_with_checksum_naming &
BackupableDBOptions::kMaskNamingFlags;
}
private:
void DeleteChildren(const std::string& dir, uint32_t file_type_filter = 0);
Status DeleteBackupInternal(BackupID backup_id);
// 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, const std::string& checksum,
const std::string& id = "", const std::string& sid = "")
: refs(0),
filename(fname),
size(sz),
checksum_hex(checksum),
db_id(id),
db_session_id(sid) {}
FileInfo(const FileInfo&) = delete;
FileInfo& operator=(const FileInfo&) = delete;
int refs;
const std::string filename;
const uint64_t size;
const std::string checksum_hex;
// DB identities
// db_id is obtained for potential usage in the future but not used
// currently
const std::string db_id;
// db_session_id appears in the backup SST filename if the table naming
// option is kUseDbSessionId
const std::string db_session_id;
};
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 GetSharedDirRel() const { return "shared"; }
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_NAMESPACE::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 GetSharedDirRel() + "/" + (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 bool UseLegacyNaming(const std::string& sid) const {
return GetNamingNoFlags() ==
BackupableDBOptions::kLegacyCrc32cAndFileSize ||
sid.empty();
}
inline bool UseInterimNaming(const std::string& sid) const {
// The indicator of SST file from early internal 6.12 release
// is a '-' in the DB session id. DB session id was made more
// concise without '-' after that.
return (GetNamingFlags() & BackupableDBOptions::kFlagMatchInterimNaming) &&
sid.find('-') != std::string::npos;
}
inline std::string GetSharedFileWithChecksum(
const std::string& file, bool has_checksum,
const std::string& checksum_hex, const uint64_t file_size,
const std::string& db_session_id) const {
assert(file.size() == 0 || file[0] != '/');
std::string file_copy = file;
if (UseLegacyNaming(db_session_id)) {
assert(has_checksum);
(void)has_checksum;
file_copy.insert(file_copy.find_last_of('.'),
"_" + ToString(ChecksumHexToInt32(checksum_hex)) + "_" +
ToString(file_size));
} else if (UseInterimNaming(db_session_id)) {
file_copy.insert(file_copy.find_last_of('.'), "_" + db_session_id);
} else {
file_copy.insert(file_copy.find_last_of('.'), "_s" + db_session_id);
if (GetNamingFlags() & BackupableDBOptions::kFlagIncludeFileSize) {
file_copy.insert(file_copy.find_last_of('.'),
"_" + ToString(file_size));
}
}
return file_copy;
}
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_NAMESPACE::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, const EnvOptions& src_env_options,
bool sync, RateLimiter* rate_limiter,
uint64_t* size = nullptr,
std::string* checksum_hex = nullptr,
uint64_t size_limit = 0,
std::function<void()> progress_callback = []() {});
Status ReadFileAndComputeChecksum(const std::string& src, Env* src_env,
const EnvOptions& src_env_options,
uint64_t size_limit,
std::string* checksum_hex);
// Obtain db_id and db_session_id from the table properties of file_path
Status GetFileDbIdentities(Env* src_env, const EnvOptions& src_env_options,
const std::string& file_path, std::string* db_id,
std::string* db_session_id);
struct CopyOrCreateResult {
uint64_t size;
std::string checksum_hex;
std::string db_id;
std::string db_session_id;
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;
EnvOptions src_env_options;
bool sync;
RateLimiter* rate_limiter;
uint64_t size_limit;
std::promise<CopyOrCreateResult> result;
std::function<void()> progress_callback;
bool verify_checksum_after_work;
std::string src_checksum_func_name;
std::string src_checksum_hex;
std::string db_id;
std::string db_session_id;
CopyOrCreateWorkItem()
: src_path(""),
dst_path(""),
contents(""),
src_env(nullptr),
dst_env(nullptr),
src_env_options(),
sync(false),
rate_limiter(nullptr),
size_limit(0),
verify_checksum_after_work(false),
src_checksum_func_name(kUnknownFileChecksumFuncName),
src_checksum_hex(""),
db_id(""),
db_session_id("") {}
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;
src_env_options = std::move(o.src_env_options);
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);
verify_checksum_after_work = o.verify_checksum_after_work;
src_checksum_func_name = std::move(o.src_checksum_func_name);
src_checksum_hex = std::move(o.src_checksum_hex);
db_id = std::move(o.db_id);
db_session_id = std::move(o.db_session_id);
return *this;
}
CopyOrCreateWorkItem(
std::string _src_path, std::string _dst_path, std::string _contents,
Env* _src_env, Env* _dst_env, EnvOptions _src_env_options, bool _sync,
RateLimiter* _rate_limiter, uint64_t _size_limit,
std::function<void()> _progress_callback = []() {},
bool _verify_checksum_after_work = false,
const std::string& _src_checksum_func_name =
kUnknownFileChecksumFuncName,
const std::string& _src_checksum_hex = "",
const std::string& _db_id = "", const std::string& _db_session_id = "")
: src_path(std::move(_src_path)),
dst_path(std::move(_dst_path)),
contents(std::move(_contents)),
src_env(_src_env),
dst_env(_dst_env),
src_env_options(std::move(_src_env_options)),
sync(_sync),
rate_limiter(_rate_limiter),
size_limit(_size_limit),
progress_callback(_progress_callback),
verify_checksum_after_work(_verify_checksum_after_work),
src_checksum_func_name(_src_checksum_func_name),
src_checksum_hex(_src_checksum_hex),
db_id(_db_id),
db_session_id(_db_session_id) {}
};
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;
std::string checksum_hex;
RestoreAfterCopyOrCreateWorkItem() : checksum_hex("") {}
RestoreAfterCopyOrCreateWorkItem(std::future<CopyOrCreateResult>&& _result,
const std::string& _checksum_hex)
: result(std::move(_result)), checksum_hex(_checksum_hex) {}
RestoreAfterCopyOrCreateWorkItem(RestoreAfterCopyOrCreateWorkItem&& o)
ROCKSDB_NOEXCEPT {
*this = std::move(o);
}
RestoreAfterCopyOrCreateWorkItem& operator=(
RestoreAfterCopyOrCreateWorkItem&& o) ROCKSDB_NOEXCEPT {
result = std::move(o.result);
checksum_hex = std::move(o.checksum_hex);
return *this;
}
};
bool initialized_;
std::mutex byte_report_mutex_;
channel<CopyOrCreateWorkItem> files_to_copy_or_create_;
std::vector<port::Thread> threads_;
std::atomic<CpuPriority> threads_cpu_priority_;
// Certain operations like PurgeOldBackups and DeleteBackup will trigger
// automatic GarbageCollect (true) unless we've already done one in this
// session and have not failed to delete backup files since then (false).
bool might_need_garbage_collect_ = true;
// 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 "/"
const EnvOptions& src_env_options, 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(),
const std::string& src_checksum_func_name = kUnknownFileChecksumFuncName,
const std::string& src_checksum_str = kUnknownFileChecksum);
// backup state data
BackupID latest_backup_id_;
BackupID latest_valid_backup_id_;
std::map<BackupID, std::unique_ptr<BackupMeta>> backups_;
std::map<BackupID, std::pair<Status, std::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
std::unique_ptr<Directory> backup_directory_;
std::unique_ptr<Directory> shared_directory_;
std::unique_ptr<Directory> meta_directory_;
std::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(const BackupableDBOptions& options, Env* env,
BackupEngine** backup_engine_ptr) {
std::unique_ptr<BackupEngineImpl> backup_engine(
new BackupEngineImpl(options, env));
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(const BackupableDBOptions& options,
Env* db_env, bool read_only)
: initialized_(false),
threads_cpu_priority_(),
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_) {
// we might need to clean up from previous crash or I/O errors
might_need_garbage_collect_ = true;
if (options_.max_valid_backups_to_open != port::kMaxInt32) {
options_.max_valid_backups_to_open = port::kMaxInt32;
ROCKS_LOG_WARN(
options_.info_log,
"`max_valid_backups_to_open` is not set to the default value. Ignoring "
"its value since BackupEngine is not 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_NAMESPACE::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());
// Insert all the (backup_id, BackupMeta) that will be loaded later
// The loading performed later will check whether there are corrupt backups
// and move the corrupt backups to corrupt_backups_
backups_.insert(std::make_pair(
backup_id, std::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
// abs_path_to_size: maps absolute paths of files in backup directory to
// their corresponding sizes
std::unordered_map<std::string, uint64_t> abs_path_to_size;
// Insert files and their sizes in backup sub-directories (shared and
// shared_checksum) to 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;
}
// Insert files and their sizes in backup sub-directories
// (private/backup_id) to abs_path_to_size
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
threads_cpu_priority_ = CpuPriority::kNormal;
threads_.reserve(options_.max_background_operations);
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
CpuPriority current_priority = CpuPriority::kNormal;
CopyOrCreateWorkItem work_item;
while (files_to_copy_or_create_.read(work_item)) {
CpuPriority priority = threads_cpu_priority_;
if (current_priority != priority) {
TEST_SYNC_POINT_CALLBACK(
"BackupEngineImpl::Initialize:SetCpuPriority", &priority);
port::SetCpuPriority(0, priority);
current_priority = priority;
}
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.src_env_options,
work_item.sync, work_item.rate_limiter, &result.size,
&result.checksum_hex, work_item.size_limit,
work_item.progress_callback);
result.db_id = work_item.db_id;
result.db_session_id = work_item.db_session_id;
if (result.status.ok() && work_item.verify_checksum_after_work) {
// unknown checksum function name implies no db table file checksum in
// db manifest; work_item.verify_checksum_after_work being true means
// backup engine has calculated its crc32c checksum for the table
// file; therefore, we are able to compare the checksums.
if (work_item.src_checksum_func_name ==
kUnknownFileChecksumFuncName ||
work_item.src_checksum_func_name == kDbFileChecksumFuncName) {
if (work_item.src_checksum_hex != result.checksum_hex) {
std::string checksum_info(
"Expected checksum is " + work_item.src_checksum_hex +
" while computed checksum is " + result.checksum_hex);
result.status =
Status::Corruption("Checksum mismatch after copying to " +
work_item.dst_path + ": " + checksum_info);
}
} else {
std::string checksum_function_info(
"Existing checksum function is " +
work_item.src_checksum_func_name +
" while provided checksum function is " +
kBackupFileChecksumFuncName);
ROCKS_LOG_INFO(
options_.info_log,
"Unable to verify checksum after copying to %s: %s\n",
work_item.dst_path.c_str(), checksum_function_info.c_str());
}
}
work_item.result.set_value(std::move(result));
}
});
}
ROCKS_LOG_INFO(options_.info_log, "Initialized BackupEngine");
return Status::OK();
}
Status BackupEngineImpl::CreateNewBackupWithMetadata(
const CreateBackupOptions& options, DB* db,
const std::string& app_metadata) {
assert(initialized_);
assert(!read_only_);
if (app_metadata.size() > kMaxAppMetaSize) {
return Status::InvalidArgument("App metadata too large");
}
if (options.decrease_background_thread_cpu_priority) {
if (options.background_thread_cpu_priority < threads_cpu_priority_) {
threads_cpu_priority_.store(options.background_thread_cpu_priority);
}
}
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.
// (If an incomplete new backup is followed by an incomplete delete
// of the latest full backup, then there could be more than one next
// id with a private dir, the last thing to be deleted in delete
// backup, but all will be cleaned up with a GarbageCollect.)
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, std::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_ = static_cast<size_t>(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;
DBOptions db_options = db->GetDBOptions();
FileChecksumGenFactory* db_checksum_factory =
db_options.file_checksum_gen_factory.get();
const std::string kFileChecksumGenFactoryName =
"FileChecksumGenCrc32cFactory";
bool compare_checksum =
db_checksum_factory != nullptr &&
db_checksum_factory->Name() == kFileChecksumGenFactoryName
? true
: false;
EnvOptions src_raw_env_options(db_options);
s = checkpoint.CreateCustomCheckpoint(
db_options,
[&](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,
const std::string& checksum_func_name,
const std::string& checksum_val) {
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);
}
EnvOptions src_env_options;
switch (type) {
case kLogFile:
src_env_options =
db_env_->OptimizeForLogRead(src_raw_env_options);
break;
case kTableFile:
src_env_options = db_env_->OptimizeForCompactionTableRead(
src_raw_env_options, ImmutableDBOptions(db_options));
break;
case kDescriptorFile:
src_env_options =
db_env_->OptimizeForManifestRead(src_raw_env_options);
break;
default:
// Other backed up files (like options file) are not read by live
// DB, so don't need to worry about avoiding mixing buffered and
// direct I/O. Just use plain defaults.
src_env_options = src_raw_env_options;
break;
}
if (st.ok()) {
st = AddBackupFileWorkItem(
live_dst_paths, backup_items_to_finish, new_backup_id,
options_.share_table_files && type == kTableFile, src_dirname,
fname, src_env_options, rate_limiter, size_bytes,
size_limit_bytes,
options_.share_files_with_checksum && type == kTableFile,
options.progress_callback, "" /* contents */,
checksum_func_name, checksum_val);
}
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,
EnvOptions() /* src_env_options */, rate_limiter, contents.size(),
0 /* size_limit */, false /* shared_checksum */,
options.progress_callback, contents);
} /* create_file_cb */,
&sequence_number, options.flush_before_backup ? 0 : port::kMaxUint64,
compare_checksum);
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_hex, result.db_id,
result.db_session_id));
}
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) {
std::unique_ptr<Directory> backup_private_directory;
backup_env_->NewDirectory(
GetAbsolutePath(GetPrivateFileRel(new_backup_id, false)),
&backup_private_directory);
if (backup_private_directory != nullptr) {
s = backup_private_directory->Fsync();
}
if (s.ok() && private_directory_ != nullptr) {
s = private_directory_->Fsync();
}
if (s.ok() && meta_directory_ != nullptr) {
s = meta_directory_->Fsync();
}
if (s.ok() && shared_directory_ != nullptr) {
s = shared_directory_->Fsync();
}
if (s.ok() && backup_directory_ != nullptr) {
s = 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
might_need_garbage_collect_ = true;
DeleteBackup(new_backup_id);
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_);
// Best effort deletion even with errors
Status overall_status = Status::OK();
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 = DeleteBackupInternal(backup_id);
if (!s.ok()) {
overall_status = s;
}
}
// Clean up after any incomplete backup deletion, potentially from
// earlier session.
if (might_need_garbage_collect_) {
auto s = GarbageCollect();
if (!s.ok() && overall_status.ok()) {
overall_status = s;
}
}
return overall_status;
}
Status BackupEngineImpl::DeleteBackup(BackupID backup_id) {
auto s1 = DeleteBackupInternal(backup_id);
auto s2 = Status::OK();
// Clean up after any incomplete backup deletion, potentially from
// earlier session.
if (might_need_garbage_collect_) {
s2 = GarbageCollect();
}
if (!s1.ok()) {
return s1;
} else {
return s2;
}
}
// Does not auto-GarbageCollect
Status BackupEngineImpl::DeleteBackupInternal(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);
}
// After removing meta file, best effort deletion even with errors.
// (Don't delete other files if we can't delete the meta file right
// now.)
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);
if (!s.ok()) {
// Trying again later might work
might_need_garbage_collect_ = true;
}
}
}
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));
ROCKS_LOG_INFO(options_.info_log, "Deleting private dir %s -- %s",
private_dir.c_str(), s.ToString().c_str());
if (!s.ok()) {
// Full gc or trying again later might work
might_need_garbage_collect_ = true;
}
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(const RestoreOptions& options,
BackupID backup_id,
const std::string& db_dir,
const std::string& wal_dir) {
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>(options.keep_log_files));
// just in case. Ignore errors
db_env_->CreateDirIfMissing(db_dir);
db_env_->CreateDirIfMissing(wal_dir);
if (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_ =
static_cast<size_t>(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_crc32c_size>,
// shared_checksum/<file_session>, shared_checksum/<file_crc32c_session>,
// 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>,
// <number>_<session>.<type>, or <number>_<checksum>_<session>.<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: Fail to parse filename " +
dst);
}
// 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_,
EnvOptions() /* src_env_options */, false, rate_limiter,
0 /* size_limit */);
RestoreAfterCopyOrCreateWorkItem after_copy_or_create_work_item(
copy_or_create_work_item.result.get_future(), file_info->checksum_hex);
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_hex != result.checksum_hex) {
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,
bool verify_with_checksum) {
// Check if backup_id is corrupted, or valid and registered
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);
// Find all existing backup files belong to 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 all files registered in backup
for (const auto& file_info : backup->GetFiles()) {
const auto abs_path = GetAbsolutePath(file_info->filename);
// check existence of the file
if (curr_abs_path_to_size.find(abs_path) == curr_abs_path_to_size.end()) {
return Status::NotFound("File missing: " + abs_path);
}
// verify file size
if (file_info->size != curr_abs_path_to_size[abs_path]) {
std::string size_info("Expected file size is " +
ToString(file_info->size) +
" while found file size is " +
ToString(curr_abs_path_to_size[abs_path]));
return Status::Corruption("File corrupted: File size mismatch for " +
abs_path + ": " + size_info);
}
if (verify_with_checksum) {
// verify file checksum
std::string checksum_hex;
ROCKS_LOG_INFO(options_.info_log, "Verifying %s checksum...\n",
abs_path.c_str());
ReadFileAndComputeChecksum(abs_path, backup_env_, EnvOptions(),
0 /* size_limit */, &checksum_hex);
if (file_info->checksum_hex != checksum_hex) {
std::string checksum_info(
"Expected checksum is " + file_info->checksum_hex +
" while computed checksum is " + checksum_hex);
return Status::Corruption("File corrupted: Checksum mismatch for " +
abs_path + ": " + checksum_info);
}
}
}
return Status::OK();
}
Status BackupEngineImpl::CopyOrCreateFile(
const std::string& src, const std::string& dst, const std::string& contents,
Env* src_env, Env* dst_env, const EnvOptions& src_env_options, bool sync,
RateLimiter* rate_limiter, uint64_t* size, std::string* checksum_hex,
uint64_t size_limit, std::function<void()> progress_callback) {
assert(src.empty() != contents.empty());
Status s;
std::unique_ptr<WritableFile> dst_file;
std::unique_ptr<SequentialFile> src_file;
EnvOptions dst_env_options;
dst_env_options.use_mmap_writes = false;
// TODO:(gzh) maybe use direct reads/writes here if possible
if (size != nullptr) {
*size = 0;
}
uint32_t 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, dst_env_options);
if (s.ok() && !src.empty()) {
s = src_env->NewSequentialFile(src, &src_file, src_env_options);
}
if (!s.ok()) {
return s;
}
std::unique_ptr<WritableFileWriter> dest_writer(new WritableFileWriter(
NewLegacyWritableFileWrapper(std::move(dst_file)), dst, dst_env_options));
std::unique_ptr<SequentialFileReader> src_reader;
std::unique_ptr<char[]> buf;
if (!src.empty()) {
src_reader.reset(new SequentialFileReader(
NewLegacySequentialFileWrapper(src_file), src));
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_
: static_cast<size_t>(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();
TEST_SYNC_POINT_CALLBACK(
"BackupEngineImpl::CopyOrCreateFile:CorruptionDuringBackup",
(src.length() > 4 && src.rfind(".sst") == src.length() - 4) ? &data
: nullptr);
if (!s.ok()) {
return s;
}
if (size != nullptr) {
*size += data.size();
}
if (checksum_hex != 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);
// Convert uint32_t checksum to hex checksum
if (checksum_hex != nullptr) {
checksum_hex->assign(ChecksumInt32ToHex(checksum_value));
}
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, const EnvOptions& src_env_options,
RateLimiter* rate_limiter, uint64_t size_bytes, uint64_t size_limit,
bool shared_checksum, std::function<void()> progress_callback,
const std::string& contents, const std::string& src_checksum_func_name,
const std::string& src_checksum_str) {
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;
std::string checksum_hex;
std::string db_id;
std::string db_session_id;
// whether the checksum for a table file is available
bool has_checksum = false;
// Whenever a default checksum function name is passed in, we will compares
// the corresponding checksum values after copying. Note that only table files
// may have a known checksum function name passed in.
//
// If no default checksum function name is passed in and db session id is not
// available, we will calculate the checksum *before* copying in two cases
// (we always calcuate checksums when copying or creating for any file types):
// a) share_files_with_checksum is true and file type is table;
// b) share_table_files is true and the file exists already.
//
// Step 0: Check if default checksum function name is passed in
if (kDbFileChecksumFuncName == src_checksum_func_name) {
if (src_checksum_str == kUnknownFileChecksum) {
return Status::Aborted("Unknown checksum value for " + fname);
}
checksum_hex = ChecksumStrToHex(src_checksum_str);
has_checksum = true;
}
// Step 1: Prepare the relative path to destination
if (shared && shared_checksum) {
if (GetNamingNoFlags() != BackupableDBOptions::kLegacyCrc32cAndFileSize) {
// Prepare db_session_id to add to the file name
// Ignore the returned status
// In the failed cases, db_id and db_session_id will be empty
GetFileDbIdentities(db_env_, src_env_options, src_dir + fname, &db_id,
&db_session_id);
}
// Calculate checksum if checksum and db session id are not available.
// If db session id is available, we will not calculate the checksum
// since the session id should suffice to avoid file name collision in
// the shared_checksum directory.
if (!has_checksum && db_session_id.empty()) {
s = ReadFileAndComputeChecksum(src_dir + fname, db_env_, src_env_options,
size_limit, &checksum_hex);
if (!s.ok()) {
return s;
}
has_checksum = true;
}
if (size_bytes == port::kMaxUint64) {
return Status::NotFound("File missing: " + src_dir + fname);
}
// dst_relative depends on the following conditions:
// 1) the naming scheme is kUseDbSessionId,
// 2) db_session_id is not empty,
// 3) checksum is available in the DB manifest.
// If 1,2,3) are satisfied, then dst_relative will be of the form:
// shared_checksum/<file_number>_<checksum>_<db_session_id>.sst
// If 1,2) are satisfied, then dst_relative will be of the form:
// shared_checksum/<file_number>_<db_session_id>.sst
// Otherwise, dst_relative is of the form
// shared_checksum/<file_number>_<checksum>_<size>.sst
dst_relative = GetSharedFileWithChecksum(
dst_relative, has_checksum, checksum_hex, size_bytes, db_session_id);
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;
}
// Step 2: Determine whether to copy or not
// 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) {
// Should be in shared directory but not a live path, check existence in
// shared directory
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;
auto find_result = backuped_file_infos_.find(dst_relative);
if (find_result == backuped_file_infos_.end() && !same_path) {
// file exists but not referenced
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 {
// file exists and referenced
if (!has_checksum) {
if (!same_path) {
assert(find_result != backuped_file_infos_.end());
// Note: to save I/O on incremental backups, we copy prior known
// checksum of the file instead of reading entire file contents
// to recompute it.
checksum_hex = find_result->second->checksum_hex;
has_checksum = true;
// Regarding corruption detection, consider:
// (a) the DB file is corrupt (since previous backup) and the backup
// file is OK: we failed to detect, but the backup is safe. DB can
// be repaired/restored once its corruption is detected.
// (b) the backup file is corrupt (since previous backup) and the
// db file is OK: we failed to detect, but the backup is corrupt.
// CreateNewBackup should support fast incremental backups and
// there's no way to support that without reading all the files.
// We might add an option for extra checks on incremental backup,
// but until then, use VerifyBackups to check existing backup data.
// (c) file name collision with legitimately different content.
// This is almost inconceivable with a well-generated DB session
// ID, but even in that case, we double check the file sizes in
// BackupMeta::AddFile.
} else {
// same_path should not happen for a standard DB, so OK to
// read file contents to check for checksum mismatch between
// two files from same DB getting same name.
s = ReadFileAndComputeChecksum(src_dir + fname, db_env_,
src_env_options, size_limit,
&checksum_hex);
if (!s.ok()) {
return s;
}
}
}
if (!db_session_id.empty()) {
ROCKS_LOG_INFO(options_.info_log,
"%s already present, with checksum %s, size %" PRIu64
" and DB session identity %s",
fname.c_str(), checksum_hex.c_str(), size_bytes,
db_session_id.c_str());
} else {
ROCKS_LOG_INFO(options_.info_log,
"%s already present, with checksum %s and size %" PRIu64,
fname.c_str(), checksum_hex.c_str(), size_bytes);
}
}
}
live_dst_paths.insert(final_dest_path);
// Step 3: Add work item
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_, src_env_options, options_.sync, rate_limiter,
size_limit, progress_callback, has_checksum, src_checksum_func_name,
checksum_hex, db_id, db_session_id);
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_hex = std::move(checksum_hex);
result.db_id = std::move(db_id);
result.db_session_id = std::move(db_session_id);
promise_result.set_value(std::move(result));
}
return s;
}
Status BackupEngineImpl::ReadFileAndComputeChecksum(
const std::string& src, Env* src_env, const EnvOptions& src_env_options,
uint64_t size_limit, std::string* checksum_hex) {
if (checksum_hex == nullptr) {
return Status::Aborted("Checksum pointer is null");
}
uint32_t checksum_value = 0;
if (size_limit == 0) {
size_limit = std::numeric_limits<uint64_t>::max();
}
std::unique_ptr<SequentialFile> src_file;
Status s = src_env->NewSequentialFile(src, &src_file, src_env_options);
if (!s.ok()) {
return s;
}
std::unique_ptr<SequentialFileReader> src_reader(
new SequentialFileReader(NewLegacySequentialFileWrapper(src_file), src));
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_ : static_cast<size_t>(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);
checksum_hex->assign(ChecksumInt32ToHex(checksum_value));
return s;
}
Status BackupEngineImpl::GetFileDbIdentities(Env* src_env,
const EnvOptions& src_env_options,
const std::string& file_path,
std::string* db_id,
std::string* db_session_id) {
assert(db_id != nullptr || db_session_id != nullptr);
Options options;
options.env = src_env;
SstFileDumper sst_reader(options, file_path,
2 * 1024 * 1024
/* readahead_size */,
false /* verify_checksum */, false /* output_hex */,
false /* decode_blob_index */, src_env_options,
true /* silent */);
const TableProperties* table_properties = nullptr;
std::shared_ptr<const TableProperties> tp;
Status s = sst_reader.getStatus();
if (s.ok()) {
// Try to get table properties from the table reader of sst_reader
if (!sst_reader.ReadTableProperties(&tp).ok()) {
// Try to use table properites from the initialization of sst_reader
table_properties = sst_reader.GetInitTableProperties();
} else {
table_properties = tp.get();
}
} else {
ROCKS_LOG_INFO(options_.info_log, "Failed to read %s: %s",
file_path.c_str(), s.ToString().c_str());
return s;
}
if (table_properties != nullptr) {
if (db_id != nullptr) {
db_id->assign(table_properties->db_id);
}
if (db_session_id != nullptr) {
db_session_id->assign(table_properties->db_session_id);
if (db_session_id->empty()) {
s = Status::NotFound("DB session identity not found in " + file_path);
ROCKS_LOG_INFO(options_.info_log, "%s", s.ToString().c_str());
return s;
}
}
return Status::OK();
} else {
s = Status::Corruption("Table properties missing in " + file_path);
ROCKS_LOG_INFO(options_.info_log, "%s", s.ToString().c_str());
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_);
// We will make a best effort to remove all garbage even in the presence
// of inconsistencies or I/O failures that inhibit finding garbage.
Status overall_status = Status::OK();
// If all goes well, we don't need another auto-GC this session
might_need_garbage_collect_ = false;
ROCKS_LOG_INFO(options_.info_log, "Starting garbage collection");
// delete obsolete shared files
for (bool with_checksum : {false, true}) {
std::vector<std::string> shared_children;
{
std::string shared_path;
if (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()) {
overall_status = s;
// Trying again later might work
might_need_garbage_collect_ = true;
}
}
for (auto& child : shared_children) {
if (child == "." || child == "..") {
continue;
}
std::string rel_fname;
if (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);
if (!s.ok()) {
// Trying again later might work
might_need_garbage_collect_ = true;
}
}
}
}
// delete obsolete private files
std::vector<std::string> private_children;
{
auto s = backup_env_->GetChildren(GetAbsolutePath(GetPrivateDirRel()),
&private_children);
if (!s.ok()) {
overall_status = s;
// Trying again later might work
might_need_garbage_collect_ = true;
}
}
for (auto& child : private_children) {
if (child == "." || child == "..") {
continue;
}
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) {
if (subchild == "." || subchild == "..") {
continue;
}
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());
if (!s.ok()) {
// Trying again later might work
might_need_garbage_collect_ = true;
}
}
// 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());
if (!s.ok()) {
// Trying again later might work
might_need_garbage_collect_ = true;
}
}
assert(overall_status.ok() || might_need_garbage_collect_);
return overall_status;
}
// ------- 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 {
// Compare sizes, because we scanned that off the filesystem on both
// ends. This is like a check in VerifyBackup.
if (itr->second->size != file_info->size) {
std::string msg = "Size mismatch for existing backup file: ";
msg.append(file_info->filename);
msg.append(" Size in backup is " + ToString(itr->second->size) +
" while size in DB is " + ToString(file_info->size));
msg.append(
" If this DB file checks as not corrupt, try deleting old"
" backups or backing up to a different backup directory.");
return Status::Corruption(msg);
}
// Note: to save I/O, this check will pass trivially on already backed
// up files that don't have the checksum in their name. And it should
// never fail for files that do have checksum in their name.
if (itr->second->checksum_hex != file_info->checksum_hex) {
// Should never reach here, but produce an appropriate corruption
// message in case we do in a release build.
assert(false);
std::string msg = "Checksum mismatch for existing backup file: ";
msg.append(file_info->filename);
msg.append(" Expected checksum is " + itr->second->checksum_hex +
" while computed checksum is " + file_info->checksum_hex);
msg.append(
" If this DB file checks as not corrupt, try deleting old"
" backups or backing up to a different backup directory.");
return Status::Corruption(msg);
}
++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)> <crc32c_value>
// <file2> <crc32(literal string)> <crc32c_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;
std::unique_ptr<SequentialFile> backup_meta_file;
s = env_->NewSequentialFile(meta_filename_, &backup_meta_file, EnvOptions());
if (!s.ok()) {
return s;
}
std::unique_ptr<SequentialFileReader> backup_meta_reader(
new SequentialFileReader(NewLegacySequentialFileWrapper(backup_meta_file),
meta_filename_));
std::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;
// WART: The checksums are crc32c, not original crc32
Slice checksum_prefix("crc32 ");
for (uint32_t i = 0; s.ok() && i < num_files; ++i) {
auto line = GetSliceUntil(&data, '\n');
// filename is relative, i.e., shared/number.sst,
// shared_checksum/number.sst, or private/backup_id/number.sst
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_NAMESPACE::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, ChecksumInt32ToHex(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;
std::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;
}
std::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 accommodate 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();
std::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();
std::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 crc32c for now, switch to something else if needed
// WART: The checksums are crc32c, not original crc32
size_t newlen =
len + file->filename.length() +
snprintf(writelen_temp, sizeof(writelen_temp), " crc32 %u\n",
ChecksumHexToInt32(file->checksum_hex));
const char* const_write = writelen_temp;
if (newlen >= buf_size) {
backup_meta_file->Append(Slice(buf.get(), len));
buf.reset();
std::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(const BackupableDBOptions& options, Env* db_env)
: backup_engine_(new BackupEngineImpl(options, db_env, true)) {}
~BackupEngineReadOnlyImpl() override {}
// The returned BackupInfos are in chronological order, which means the
// latest backup comes last.
void GetBackupInfo(std::vector<BackupInfo>* backup_info) override {
backup_engine_->GetBackupInfo(backup_info);
}
void GetCorruptedBackups(std::vector<BackupID>* corrupt_backup_ids) override {
backup_engine_->GetCorruptedBackups(corrupt_backup_ids);
}
using BackupEngineReadOnly::RestoreDBFromBackup;
Status RestoreDBFromBackup(const RestoreOptions& options, BackupID backup_id,
const std::string& db_dir,
const std::string& wal_dir) override {
return backup_engine_->RestoreDBFromBackup(options, backup_id, db_dir,
wal_dir);
}
using BackupEngineReadOnly::RestoreDBFromLatestBackup;
Status RestoreDBFromLatestBackup(const RestoreOptions& options,
const std::string& db_dir,
const std::string& wal_dir) override {
return backup_engine_->RestoreDBFromLatestBackup(options, db_dir, wal_dir);
}
Status VerifyBackup(BackupID backup_id,
bool verify_with_checksum = false) override {
return backup_engine_->VerifyBackup(backup_id, verify_with_checksum);
}
Status Initialize() { return backup_engine_->Initialize(); }
private:
std::unique_ptr<BackupEngineImpl> backup_engine_;
};
Status BackupEngineReadOnly::Open(const BackupableDBOptions& options, Env* env,
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(options, env));
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_NAMESPACE
#endif // ROCKSDB_LITE
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