rocksdb/db/db_filesnapshot.cc
Bo Wang bcabee737f Improve comments for some files (#9793)
Summary:
Update the comments, e.g. fixing typo, formatting, etc.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9793

Reviewed By: jay-zhuang

Differential Revision: D35323989

Pulled By: gitbw95

fbshipit-source-id: 4a72fc02b67abaae8be0d1439b68f9967a68052d
2022-04-01 16:06:14 -07:00

405 lines
13 KiB
C++

// 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).
//
#ifndef ROCKSDB_LITE
#include <algorithm>
#include <cstdint>
#include <memory>
#include <string>
#include <vector>
#include "db/db_impl/db_impl.h"
#include "db/job_context.h"
#include "db/version_set.h"
#include "file/file_util.h"
#include "file/filename.h"
#include "logging/logging.h"
#include "port/port.h"
#include "rocksdb/db.h"
#include "rocksdb/env.h"
#include "rocksdb/metadata.h"
#include "rocksdb/types.h"
#include "test_util/sync_point.h"
#include "util/file_checksum_helper.h"
#include "util/mutexlock.h"
namespace ROCKSDB_NAMESPACE {
Status DBImpl::FlushForGetLiveFiles() {
mutex_.AssertHeld();
// flush all dirty data to disk.
Status status;
if (immutable_db_options_.atomic_flush) {
autovector<ColumnFamilyData*> cfds;
SelectColumnFamiliesForAtomicFlush(&cfds);
mutex_.Unlock();
status =
AtomicFlushMemTables(cfds, FlushOptions(), FlushReason::kGetLiveFiles);
if (status.IsColumnFamilyDropped()) {
status = Status::OK();
}
mutex_.Lock();
} else {
for (auto cfd : versions_->GetRefedColumnFamilySet()) {
if (cfd->IsDropped()) {
continue;
}
mutex_.Unlock();
status = FlushMemTable(cfd, FlushOptions(), FlushReason::kGetLiveFiles);
TEST_SYNC_POINT("DBImpl::GetLiveFiles:1");
TEST_SYNC_POINT("DBImpl::GetLiveFiles:2");
mutex_.Lock();
if (!status.ok() && !status.IsColumnFamilyDropped()) {
break;
} else if (status.IsColumnFamilyDropped()) {
status = Status::OK();
}
}
}
return status;
}
Status DBImpl::GetLiveFiles(std::vector<std::string>& ret,
uint64_t* manifest_file_size,
bool flush_memtable) {
*manifest_file_size = 0;
mutex_.Lock();
if (flush_memtable) {
Status status = FlushForGetLiveFiles();
if (!status.ok()) {
mutex_.Unlock();
ROCKS_LOG_ERROR(immutable_db_options_.info_log, "Cannot Flush data %s\n",
status.ToString().c_str());
return status;
}
}
// Make a set of all of the live table and blob files
std::vector<uint64_t> live_table_files;
std::vector<uint64_t> live_blob_files;
for (auto cfd : *versions_->GetColumnFamilySet()) {
if (cfd->IsDropped()) {
continue;
}
cfd->current()->AddLiveFiles(&live_table_files, &live_blob_files);
}
ret.clear();
ret.reserve(live_table_files.size() + live_blob_files.size() +
3); // for CURRENT + MANIFEST + OPTIONS
// create names of the live files. The names are not absolute
// paths, instead they are relative to dbname_.
for (const auto& table_file_number : live_table_files) {
ret.emplace_back(MakeTableFileName("", table_file_number));
}
for (const auto& blob_file_number : live_blob_files) {
ret.emplace_back(BlobFileName("", blob_file_number));
}
ret.emplace_back(CurrentFileName(""));
ret.emplace_back(DescriptorFileName("", versions_->manifest_file_number()));
// The OPTIONS file number is zero in read-write mode when OPTIONS file
// writing failed and the DB was configured with
// `fail_if_options_file_error == false`. In read-only mode the OPTIONS file
// number is zero when no OPTIONS file exist at all. In those cases we do not
// record any OPTIONS file in the live file list.
if (versions_->options_file_number() != 0) {
ret.emplace_back(OptionsFileName("", versions_->options_file_number()));
}
// find length of manifest file while holding the mutex lock
*manifest_file_size = versions_->manifest_file_size();
mutex_.Unlock();
return Status::OK();
}
Status DBImpl::GetSortedWalFiles(VectorLogPtr& files) {
// If caller disabled deletions, this function should return files that are
// guaranteed not to be deleted until deletions are re-enabled. We need to
// wait for pending purges to finish since WalManager doesn't know which
// files are going to be purged. Additional purges won't be scheduled as
// long as deletions are disabled (so the below loop must terminate).
// Also note that we disable deletions anyway to avoid the case where a
// file is deleted in the middle of the scan, causing IO error.
Status deletions_disabled = DisableFileDeletions();
{
InstrumentedMutexLock l(&mutex_);
while (pending_purge_obsolete_files_ > 0 || bg_purge_scheduled_ > 0) {
bg_cv_.Wait();
}
}
Status s = wal_manager_.GetSortedWalFiles(files);
// DisableFileDeletions / EnableFileDeletions not supported in read-only DB
if (deletions_disabled.ok()) {
Status s2 = EnableFileDeletions(/*force*/ false);
assert(s2.ok());
s2.PermitUncheckedError();
} else {
assert(deletions_disabled.IsNotSupported());
}
return s;
}
Status DBImpl::GetCurrentWalFile(std::unique_ptr<LogFile>* current_log_file) {
uint64_t current_logfile_number;
{
InstrumentedMutexLock l(&mutex_);
current_logfile_number = logfile_number_;
}
return wal_manager_.GetLiveWalFile(current_logfile_number, current_log_file);
}
Status DBImpl::GetLiveFilesStorageInfo(
const LiveFilesStorageInfoOptions& opts,
std::vector<LiveFileStorageInfo>* files) {
// To avoid returning partial results, only move results to files on success.
assert(files);
files->clear();
std::vector<LiveFileStorageInfo> results;
// NOTE: This implementation was largely migrated from Checkpoint.
Status s;
VectorLogPtr live_wal_files;
bool flush_memtable = true;
if (!immutable_db_options_.allow_2pc) {
if (opts.wal_size_for_flush == port::kMaxUint64) {
flush_memtable = false;
} else if (opts.wal_size_for_flush > 0) {
// If the outstanding log files are small, we skip the flush.
s = 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 < opts.wal_size_for_flush) {
flush_memtable = false;
}
live_wal_files.clear();
}
}
// This is a modified version of GetLiveFiles, to get access to more
// metadata.
mutex_.Lock();
if (flush_memtable) {
Status status = FlushForGetLiveFiles();
if (!status.ok()) {
mutex_.Unlock();
ROCKS_LOG_ERROR(immutable_db_options_.info_log, "Cannot Flush data %s\n",
status.ToString().c_str());
return status;
}
}
// Make a set of all of the live table and blob files
for (auto cfd : *versions_->GetColumnFamilySet()) {
if (cfd->IsDropped()) {
continue;
}
VersionStorageInfo& vsi = *cfd->current()->storage_info();
auto& cf_paths = cfd->ioptions()->cf_paths;
auto GetDir = [&](size_t path_id) {
// Matching TableFileName() behavior
if (path_id >= cf_paths.size()) {
assert(false);
return cf_paths.back().path;
} else {
return cf_paths[path_id].path;
}
};
for (int level = 0; level < vsi.num_levels(); ++level) {
const auto& level_files = vsi.LevelFiles(level);
for (const auto& meta : level_files) {
assert(meta);
results.emplace_back();
LiveFileStorageInfo& info = results.back();
info.relative_filename = MakeTableFileName(meta->fd.GetNumber());
info.directory = GetDir(meta->fd.GetPathId());
info.file_number = meta->fd.GetNumber();
info.file_type = kTableFile;
info.size = meta->fd.GetFileSize();
if (opts.include_checksum_info) {
info.file_checksum_func_name = meta->file_checksum_func_name;
info.file_checksum = meta->file_checksum;
if (info.file_checksum_func_name.empty()) {
info.file_checksum_func_name = kUnknownFileChecksumFuncName;
info.file_checksum = kUnknownFileChecksum;
}
}
info.temperature = meta->temperature;
}
}
const auto& blob_files = vsi.GetBlobFiles();
for (const auto& meta : blob_files) {
assert(meta);
results.emplace_back();
LiveFileStorageInfo& info = results.back();
info.relative_filename = BlobFileName(meta->GetBlobFileNumber());
info.directory = GetDir(/* path_id */ 0);
info.file_number = meta->GetBlobFileNumber();
info.file_type = kBlobFile;
info.size = meta->GetBlobFileSize();
if (opts.include_checksum_info) {
info.file_checksum_func_name = meta->GetChecksumMethod();
info.file_checksum = meta->GetChecksumValue();
if (info.file_checksum_func_name.empty()) {
info.file_checksum_func_name = kUnknownFileChecksumFuncName;
info.file_checksum = kUnknownFileChecksum;
}
}
// TODO?: info.temperature
}
}
// Capture some final info before releasing mutex
const uint64_t manifest_number = versions_->manifest_file_number();
const uint64_t manifest_size = versions_->manifest_file_size();
const uint64_t options_number = versions_->options_file_number();
const uint64_t options_size = versions_->options_file_size_;
const uint64_t min_log_num = MinLogNumberToKeep();
mutex_.Unlock();
std::string manifest_fname = DescriptorFileName(manifest_number);
{ // MANIFEST
results.emplace_back();
LiveFileStorageInfo& info = results.back();
info.relative_filename = manifest_fname;
info.directory = GetName();
info.file_number = manifest_number;
info.file_type = kDescriptorFile;
info.size = manifest_size;
info.trim_to_size = true;
if (opts.include_checksum_info) {
info.file_checksum_func_name = kUnknownFileChecksumFuncName;
info.file_checksum = kUnknownFileChecksum;
}
}
{ // CURRENT
results.emplace_back();
LiveFileStorageInfo& info = results.back();
info.relative_filename = kCurrentFileName;
info.directory = GetName();
info.file_type = kCurrentFile;
// CURRENT could be replaced so we have to record the contents as needed.
info.replacement_contents = manifest_fname + "\n";
info.size = manifest_fname.size() + 1;
if (opts.include_checksum_info) {
info.file_checksum_func_name = kUnknownFileChecksumFuncName;
info.file_checksum = kUnknownFileChecksum;
}
}
// The OPTIONS file number is zero in read-write mode when OPTIONS file
// writing failed and the DB was configured with
// `fail_if_options_file_error == false`. In read-only mode the OPTIONS file
// number is zero when no OPTIONS file exist at all. In those cases we do not
// record any OPTIONS file in the live file list.
if (options_number != 0) {
results.emplace_back();
LiveFileStorageInfo& info = results.back();
info.relative_filename = OptionsFileName(options_number);
info.directory = GetName();
info.file_number = options_number;
info.file_type = kOptionsFile;
info.size = options_size;
if (opts.include_checksum_info) {
info.file_checksum_func_name = kUnknownFileChecksumFuncName;
info.file_checksum = kUnknownFileChecksum;
}
}
// Some legacy testing stuff TODO: carefully clean up obsolete parts
TEST_SYNC_POINT("CheckpointImpl::CreateCheckpoint:FlushDone");
TEST_SYNC_POINT("CheckpointImpl::CreateCheckpoint:SavedLiveFiles1");
TEST_SYNC_POINT("CheckpointImpl::CreateCheckpoint:SavedLiveFiles2");
if (s.ok()) {
s = FlushWAL(false /* sync */);
}
TEST_SYNC_POINT("CheckpointImpl::CreateCustomCheckpoint:AfterGetLive1");
TEST_SYNC_POINT("CheckpointImpl::CreateCustomCheckpoint:AfterGetLive2");
// If we have more than one column family, we also need to get WAL files.
if (s.ok()) {
s = GetSortedWalFiles(live_wal_files);
}
if (!s.ok()) {
return s;
}
size_t wal_size = live_wal_files.size();
ROCKS_LOG_INFO(immutable_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.
auto wal_dir = immutable_db_options_.GetWalDir();
for (size_t i = 0; s.ok() && i < wal_size; ++i) {
if ((live_wal_files[i]->Type() == kAliveLogFile) &&
(!flush_memtable || live_wal_files[i]->LogNumber() >= min_log_num)) {
results.emplace_back();
LiveFileStorageInfo& info = results.back();
auto f = live_wal_files[i]->PathName();
assert(!f.empty() && f[0] == '/');
info.relative_filename = f.substr(1);
info.directory = wal_dir;
info.file_number = live_wal_files[i]->LogNumber();
info.file_type = kWalFile;
info.size = live_wal_files[i]->SizeFileBytes();
// Only last should need to be trimmed
info.trim_to_size = (i + 1 == wal_size);
if (opts.include_checksum_info) {
info.file_checksum_func_name = kUnknownFileChecksumFuncName;
info.file_checksum = kUnknownFileChecksum;
}
}
}
if (s.ok()) {
// Only move results to output on success.
*files = std::move(results);
}
return s;
}
} // namespace ROCKSDB_NAMESPACE
#endif // ROCKSDB_LITE