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rocksdb/utilities/checkpoint/checkpoint_impl.cc

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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) 2012 Facebook.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef ROCKSDB_LITE
#include "utilities/checkpoint/checkpoint_impl.h"
#include <algorithm>
#include <cinttypes>
#include <string>
#include <vector>
#include "db/wal_manager.h"
#include "file/file_util.h"
#include "file/filename.h"
#include "port/port.h"
#include "rocksdb/db.h"
#include "rocksdb/env.h"
#include "rocksdb/metadata.h"
#include "rocksdb/transaction_log.h"
#include "rocksdb/utilities/checkpoint.h"
#include "test_util/sync_point.h"
namespace rocksdb {
Status Checkpoint::Create(DB* db, Checkpoint** checkpoint_ptr) {
*checkpoint_ptr = new CheckpointImpl(db);
return Status::OK();
}
Status Checkpoint::CreateCheckpoint(const std::string& /*checkpoint_dir*/,
uint64_t /*log_size_for_flush*/) {
return Status::NotSupported("");
}
void CheckpointImpl::CleanStagingDirectory(
const std::string& full_private_path, Logger* info_log) {
std::vector<std::string> subchildren;
Status s = db_->GetEnv()->FileExists(full_private_path);
if (s.IsNotFound()) {
return;
}
ROCKS_LOG_INFO(info_log, "File exists %s -- %s",
full_private_path.c_str(), s.ToString().c_str());
db_->GetEnv()->GetChildren(full_private_path, &subchildren);
for (auto& subchild : subchildren) {
std::string subchild_path = full_private_path + "/" + subchild;
s = db_->GetEnv()->DeleteFile(subchild_path);
ROCKS_LOG_INFO(info_log, "Delete file %s -- %s",
subchild_path.c_str(), s.ToString().c_str());
}
// finally delete the private dir
s = db_->GetEnv()->DeleteDir(full_private_path);
ROCKS_LOG_INFO(info_log, "Delete dir %s -- %s",
full_private_path.c_str(), s.ToString().c_str());
}
Status Checkpoint::ExportColumnFamily(
ColumnFamilyHandle* /*handle*/, const std::string& /*export_dir*/,
ExportImportFilesMetaData** /*metadata*/) {
return Status::NotSupported("");
}
// Builds an openable snapshot of RocksDB
Status CheckpointImpl::CreateCheckpoint(const std::string& checkpoint_dir,
uint64_t log_size_for_flush) {
DBOptions db_options = db_->GetDBOptions();
Status s = db_->GetEnv()->FileExists(checkpoint_dir);
if (s.ok()) {
return Status::InvalidArgument("Directory exists");
} else if (!s.IsNotFound()) {
assert(s.IsIOError());
return s;
}
ROCKS_LOG_INFO(
db_options.info_log,
"Started the snapshot process -- creating snapshot in directory %s",
checkpoint_dir.c_str());
size_t final_nonslash_idx = checkpoint_dir.find_last_not_of('/');
if (final_nonslash_idx == std::string::npos) {
// npos means it's only slashes or empty. Non-empty means it's the root
// directory, but it shouldn't be because we verified above the directory
// doesn't exist.
assert(checkpoint_dir.empty());
return Status::InvalidArgument("invalid checkpoint directory name");
}
std::string full_private_path =
checkpoint_dir.substr(0, final_nonslash_idx + 1) + ".tmp";
ROCKS_LOG_INFO(
db_options.info_log,
"Snapshot process -- using temporary directory %s",
full_private_path.c_str());
CleanStagingDirectory(full_private_path, db_options.info_log.get());
// create snapshot directory
s = db_->GetEnv()->CreateDir(full_private_path);
uint64_t sequence_number = 0;
if (s.ok()) {
db_->DisableFileDeletions();
s = CreateCustomCheckpoint(
db_options,
[&](const std::string& src_dirname, const std::string& fname,
FileType) {
ROCKS_LOG_INFO(db_options.info_log, "Hard Linking %s", fname.c_str());
return db_->GetEnv()->LinkFile(src_dirname + fname,
full_private_path + fname);
} /* link_file_cb */,
[&](const std::string& src_dirname, const std::string& fname,
uint64_t size_limit_bytes, FileType) {
ROCKS_LOG_INFO(db_options.info_log, "Copying %s", fname.c_str());
return CopyFile(db_->GetEnv(), src_dirname + fname,
full_private_path + fname, size_limit_bytes,
db_options.use_fsync);
} /* copy_file_cb */,
[&](const std::string& fname, const std::string& contents, FileType) {
ROCKS_LOG_INFO(db_options.info_log, "Creating %s", fname.c_str());
return CreateFile(db_->GetEnv(), full_private_path + fname, contents,
db_options.use_fsync);
} /* create_file_cb */,
&sequence_number, log_size_for_flush);
// we copied all the files, enable file deletions
db_->EnableFileDeletions(false);
}
if (s.ok()) {
// move tmp private backup to real snapshot directory
s = db_->GetEnv()->RenameFile(full_private_path, checkpoint_dir);
}
if (s.ok()) {
std::unique_ptr<Directory> checkpoint_directory;
db_->GetEnv()->NewDirectory(checkpoint_dir, &checkpoint_directory);
if (checkpoint_directory != nullptr) {
s = checkpoint_directory->Fsync();
}
}
if (s.ok()) {
// here we know that we succeeded and installed the new snapshot
ROCKS_LOG_INFO(db_options.info_log, "Snapshot DONE. All is good");
ROCKS_LOG_INFO(db_options.info_log, "Snapshot sequence number: %" PRIu64,
sequence_number);
} else {
// clean all the files we might have created
ROCKS_LOG_INFO(db_options.info_log, "Snapshot failed -- %s",
s.ToString().c_str());
CleanStagingDirectory(full_private_path, db_options.info_log.get());
}
return s;
}
Status CheckpointImpl::CreateCustomCheckpoint(
const DBOptions& db_options,
std::function<Status(const std::string& src_dirname,
const std::string& src_fname, FileType type)>
link_file_cb,
std::function<Status(const std::string& src_dirname,
const std::string& src_fname,
uint64_t size_limit_bytes, FileType type)>
copy_file_cb,
std::function<Status(const std::string& fname, const std::string& contents,
FileType type)>
create_file_cb,
uint64_t* sequence_number, uint64_t log_size_for_flush) {
Status s;
std::vector<std::string> live_files;
uint64_t manifest_file_size = 0;
uint64_t min_log_num = port::kMaxUint64;
*sequence_number = db_->GetLatestSequenceNumber();
bool same_fs = true;
VectorLogPtr live_wal_files;
bool flush_memtable = true;
if (s.ok()) {
if (!db_options.allow_2pc) {
if (log_size_for_flush == port::kMaxUint64) {
flush_memtable = false;
} else if (log_size_for_flush > 0) {
// If out standing log files are small, we skip the flush.
s = db_->GetSortedWalFiles(live_wal_files);
if (!s.ok()) {
return s;
}
// Don't flush column families if total log size is smaller than
// log_size_for_flush. We copy the log files instead.
// We may be able to cover 2PC case too.
uint64_t total_wal_size = 0;
for (auto& wal : live_wal_files) {
total_wal_size += wal->SizeFileBytes();
}
if (total_wal_size < log_size_for_flush) {
flush_memtable = false;
}
live_wal_files.clear();
}
}
// this will return live_files prefixed with "/"
s = db_->GetLiveFiles(live_files, &manifest_file_size, flush_memtable);
if (s.ok() && db_options.allow_2pc) {
// If 2PC is enabled, we need to get minimum log number after the flush.
// Need to refetch the live files to recapture the snapshot.
if (!db_->GetIntProperty(DB::Properties::kMinLogNumberToKeep,
&min_log_num)) {
return Status::InvalidArgument(
"2PC enabled but cannot fine the min log number to keep.");
}
// We need to refetch live files with flush to handle this case:
// A previous 000001.log contains the prepare record of transaction tnx1.
// The current log file is 000002.log, and sequence_number points to this
// file.
// After calling GetLiveFiles(), 000003.log is created.
// Then tnx1 is committed. The commit record is written to 000003.log.
// Now we fetch min_log_num, which will be 3.
// Then only 000002.log and 000003.log will be copied, and 000001.log will
// be skipped. 000003.log contains commit message of tnx1, but we don't
// have respective prepare record for it.
// In order to avoid this situation, we need to force flush to make sure
// all transactions committed before getting min_log_num will be flushed
// to SST files.
// We cannot get min_log_num before calling the GetLiveFiles() for the
// first time, because if we do that, all the logs files will be included,
// far more than needed.
s = db_->GetLiveFiles(live_files, &manifest_file_size, flush_memtable);
}
TEST_SYNC_POINT("CheckpointImpl::CreateCheckpoint:SavedLiveFiles1");
TEST_SYNC_POINT("CheckpointImpl::CreateCheckpoint:SavedLiveFiles2");
db_->FlushWAL(false /* sync */);
}
// if we have more than one column family, we need to also get WAL files
if (s.ok()) {
s = db_->GetSortedWalFiles(live_wal_files);
}
if (!s.ok()) {
return s;
}
size_t wal_size = live_wal_files.size();
// copy/hard link live_files
std::string manifest_fname, current_fname;
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) {
s = Status::Corruption("Can't parse file name. This is very bad");
break;
}
// we should only get sst, options, manifest and current files here
assert(type == kTableFile || type == kDescriptorFile ||
type == kCurrentFile || type == kOptionsFile);
assert(live_files[i].size() > 0 && live_files[i][0] == '/');
if (type == kCurrentFile) {
// We will craft the current file manually to ensure it's consistent with
// the manifest number. This is necessary because current's file contents
// can change during checkpoint creation.
current_fname = live_files[i];
continue;
} else if (type == kDescriptorFile) {
manifest_fname = live_files[i];
}
std::string src_fname = live_files[i];
// rules:
// * if it's kTableFile, then it's shared
// * if it's kDescriptorFile, limit the size to manifest_file_size
// * always copy if cross-device link
if ((type == kTableFile) && same_fs) {
s = link_file_cb(db_->GetName(), src_fname, type);
if (s.IsNotSupported()) {
same_fs = false;
s = Status::OK();
}
}
if ((type != kTableFile) || (!same_fs)) {
s = copy_file_cb(db_->GetName(), src_fname,
(type == kDescriptorFile) ? manifest_file_size : 0,
type);
}
}
if (s.ok() && !current_fname.empty() && !manifest_fname.empty()) {
create_file_cb(current_fname, manifest_fname.substr(1) + "\n",
kCurrentFile);
}
ROCKS_LOG_INFO(db_options.info_log, "Number of log files %" ROCKSDB_PRIszt,
live_wal_files.size());
// Link WAL files. Copy exact size of last one because it is the only one
// that has changes after the last flush.
for (size_t i = 0; s.ok() && i < wal_size; ++i) {
if ((live_wal_files[i]->Type() == kAliveLogFile) &&
(!flush_memtable ||
live_wal_files[i]->StartSequence() >= *sequence_number ||
live_wal_files[i]->LogNumber() >= min_log_num)) {
if (i + 1 == wal_size) {
s = copy_file_cb(db_options.wal_dir, live_wal_files[i]->PathName(),
live_wal_files[i]->SizeFileBytes(), kLogFile);
break;
}
if (same_fs) {
// we only care about live log files
s = link_file_cb(db_options.wal_dir, live_wal_files[i]->PathName(),
kLogFile);
if (s.IsNotSupported()) {
same_fs = false;
s = Status::OK();
}
}
if (!same_fs) {
s = copy_file_cb(db_options.wal_dir, live_wal_files[i]->PathName(), 0,
kLogFile);
}
}
}
return s;
}
// Exports all live SST files of a specified Column Family onto export_dir,
// returning SST files information in metadata.
Status CheckpointImpl::ExportColumnFamily(
ColumnFamilyHandle* handle, const std::string& export_dir,
ExportImportFilesMetaData** metadata) {
auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(handle);
const auto cf_name = cfh->GetName();
const auto db_options = db_->GetDBOptions();
assert(metadata != nullptr);
assert(*metadata == nullptr);
auto s = db_->GetEnv()->FileExists(export_dir);
if (s.ok()) {
return Status::InvalidArgument("Specified export_dir exists");
} else if (!s.IsNotFound()) {
assert(s.IsIOError());
return s;
}
const auto final_nonslash_idx = export_dir.find_last_not_of('/');
if (final_nonslash_idx == std::string::npos) {
return Status::InvalidArgument("Specified export_dir invalid");
}
ROCKS_LOG_INFO(db_options.info_log,
"[%s] export column family onto export directory %s",
cf_name.c_str(), export_dir.c_str());
// Create a temporary export directory.
const auto tmp_export_dir =
export_dir.substr(0, final_nonslash_idx + 1) + ".tmp";
s = db_->GetEnv()->CreateDir(tmp_export_dir);
if (s.ok()) {
s = db_->Flush(rocksdb::FlushOptions(), handle);
}
ColumnFamilyMetaData db_metadata;
if (s.ok()) {
// Export live sst files with file deletions disabled.
s = db_->DisableFileDeletions();
if (s.ok()) {
db_->GetColumnFamilyMetaData(handle, &db_metadata);
s = ExportFilesInMetaData(
db_options, db_metadata,
[&](const std::string& src_dirname, const std::string& fname) {
ROCKS_LOG_INFO(db_options.info_log, "[%s] HardLinking %s",
cf_name.c_str(), fname.c_str());
return db_->GetEnv()->LinkFile(src_dirname + fname,
tmp_export_dir + fname);
} /*link_file_cb*/,
[&](const std::string& src_dirname, const std::string& fname) {
ROCKS_LOG_INFO(db_options.info_log, "[%s] Copying %s",
cf_name.c_str(), fname.c_str());
return CopyFile(db_->GetEnv(), src_dirname + fname,
tmp_export_dir + fname, 0, db_options.use_fsync);
} /*copy_file_cb*/);
const auto enable_status = db_->EnableFileDeletions(false /*force*/);
if (s.ok()) {
s = enable_status;
}
}
}
auto moved_to_user_specified_dir = false;
if (s.ok()) {
// Move temporary export directory to the actual export directory.
s = db_->GetEnv()->RenameFile(tmp_export_dir, export_dir);
}
if (s.ok()) {
// Fsync export directory.
moved_to_user_specified_dir = true;
std::unique_ptr<Directory> dir_ptr;
s = db_->GetEnv()->NewDirectory(export_dir, &dir_ptr);
if (s.ok()) {
assert(dir_ptr != nullptr);
s = dir_ptr->Fsync();
}
}
if (s.ok()) {
// Export of files succeeded. Fill in the metadata information.
auto result_metadata = new ExportImportFilesMetaData();
result_metadata->db_comparator_name = handle->GetComparator()->Name();
for (const auto& level_metadata : db_metadata.levels) {
for (const auto& file_metadata : level_metadata.files) {
LiveFileMetaData live_file_metadata;
live_file_metadata.size = file_metadata.size;
live_file_metadata.name = std::move(file_metadata.name);
live_file_metadata.db_path = export_dir;
live_file_metadata.smallest_seqno = file_metadata.smallest_seqno;
live_file_metadata.largest_seqno = file_metadata.largest_seqno;
live_file_metadata.smallestkey = std::move(file_metadata.smallestkey);
live_file_metadata.largestkey = std::move(file_metadata.largestkey);
live_file_metadata.level = level_metadata.level;
result_metadata->files.push_back(live_file_metadata);
}
*metadata = result_metadata;
}
ROCKS_LOG_INFO(db_options.info_log, "[%s] Export succeeded.",
cf_name.c_str());
} else {
// Failure: Clean up all the files/directories created.
ROCKS_LOG_INFO(db_options.info_log, "[%s] Export failed. %s",
cf_name.c_str(), s.ToString().c_str());
std::vector<std::string> subchildren;
const auto cleanup_dir =
moved_to_user_specified_dir ? export_dir : tmp_export_dir;
db_->GetEnv()->GetChildren(cleanup_dir, &subchildren);
for (const auto& subchild : subchildren) {
const auto subchild_path = cleanup_dir + "/" + subchild;
const auto status = db_->GetEnv()->DeleteFile(subchild_path);
if (!status.ok()) {
ROCKS_LOG_WARN(db_options.info_log, "Failed to cleanup file %s: %s",
subchild_path.c_str(), status.ToString().c_str());
}
}
const auto status = db_->GetEnv()->DeleteDir(cleanup_dir);
if (!status.ok()) {
ROCKS_LOG_WARN(db_options.info_log, "Failed to cleanup dir %s: %s",
cleanup_dir.c_str(), status.ToString().c_str());
}
}
return s;
}
Status CheckpointImpl::ExportFilesInMetaData(
const DBOptions& db_options, const ColumnFamilyMetaData& metadata,
std::function<Status(const std::string& src_dirname,
const std::string& src_fname)>
link_file_cb,
std::function<Status(const std::string& src_dirname,
const std::string& src_fname)>
copy_file_cb) {
Status s;
auto hardlink_file = true;
// Copy/hard link files in metadata.
size_t num_files = 0;
for (const auto& level_metadata : metadata.levels) {
for (const auto& file_metadata : level_metadata.files) {
uint64_t number;
FileType type;
const auto ok = ParseFileName(file_metadata.name, &number, &type);
if (!ok) {
s = Status::Corruption("Could not parse file name");
break;
}
// We should only get sst files here.
assert(type == kTableFile);
assert(file_metadata.size > 0 && file_metadata.name[0] == '/');
const auto src_fname = file_metadata.name;
++num_files;
if (hardlink_file) {
s = link_file_cb(db_->GetName(), src_fname);
if (num_files == 1 && s.IsNotSupported()) {
// Fallback to copy if link failed due to cross-device directories.
hardlink_file = false;
s = Status::OK();
}
}
if (!hardlink_file) {
s = copy_file_cb(db_->GetName(), src_fname);
}
if (!s.ok()) {
break;
}
}
}
ROCKS_LOG_INFO(db_options.info_log, "Number of table files %" ROCKSDB_PRIszt,
num_files);
return s;
}
} // namespace rocksdb
#endif // ROCKSDB_LITE
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