Revision f0e8731b72c254da2843d64d27dc7c419bef4bd0 authored by Tongliang Liao on 11 May 2020, 17:26:18 UTC, committed by Facebook GitHub Bot on 11 May 2020, 17:28:49 UTC
Summary: Related to some discussion in https://github.com/facebook/rocksdb/issues/6179 Pull Request resolved: https://github.com/facebook/rocksdb/pull/6771 Reviewed By: zhichao-cao Differential Revision: D21340117 fbshipit-source-id: a1af0ba4865bb13c8c817851d6f6c4056191b3fe
1 parent 3a1c29d
wal_manager.cc
// 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.
#include "db/wal_manager.h"
#include <algorithm>
#include <cinttypes>
#include <memory>
#include <vector>
#include "db/log_reader.h"
#include "db/log_writer.h"
#include "db/transaction_log_impl.h"
#include "db/write_batch_internal.h"
#include "file/file_util.h"
#include "file/filename.h"
#include "file/sequence_file_reader.h"
#include "logging/logging.h"
#include "port/port.h"
#include "rocksdb/env.h"
#include "rocksdb/options.h"
#include "rocksdb/write_batch.h"
#include "test_util/sync_point.h"
#include "util/cast_util.h"
#include "util/coding.h"
#include "util/mutexlock.h"
#include "util/string_util.h"
namespace ROCKSDB_NAMESPACE {
#ifndef ROCKSDB_LITE
Status WalManager::DeleteFile(const std::string& fname, uint64_t number) {
auto s = env_->DeleteFile(db_options_.wal_dir + "/" + fname);
if (s.ok()) {
MutexLock l(&read_first_record_cache_mutex_);
read_first_record_cache_.erase(number);
}
return s;
}
Status WalManager::GetSortedWalFiles(VectorLogPtr& files) {
// First get sorted files in db dir, then get sorted files from archived
// dir, to avoid a race condition where a log file is moved to archived
// dir in between.
Status s;
// list wal files in main db dir.
VectorLogPtr logs;
s = GetSortedWalsOfType(db_options_.wal_dir, logs, kAliveLogFile);
if (!s.ok()) {
return s;
}
// Reproduce the race condition where a log file is moved
// to archived dir, between these two sync points, used in
// (DBTest,TransactionLogIteratorRace)
TEST_SYNC_POINT("WalManager::GetSortedWalFiles:1");
TEST_SYNC_POINT("WalManager::GetSortedWalFiles:2");
files.clear();
// list wal files in archive dir.
std::string archivedir = ArchivalDirectory(db_options_.wal_dir);
Status exists = env_->FileExists(archivedir);
if (exists.ok()) {
s = GetSortedWalsOfType(archivedir, files, kArchivedLogFile);
if (!s.ok()) {
return s;
}
} else if (!exists.IsNotFound()) {
assert(s.IsIOError());
return s;
}
uint64_t latest_archived_log_number = 0;
if (!files.empty()) {
latest_archived_log_number = files.back()->LogNumber();
ROCKS_LOG_INFO(db_options_.info_log, "Latest Archived log: %" PRIu64,
latest_archived_log_number);
}
files.reserve(files.size() + logs.size());
for (auto& log : logs) {
if (log->LogNumber() > latest_archived_log_number) {
files.push_back(std::move(log));
} else {
// When the race condition happens, we could see the
// same log in both db dir and archived dir. Simply
// ignore the one in db dir. Note that, if we read
// archived dir first, we would have missed the log file.
ROCKS_LOG_WARN(db_options_.info_log, "%s already moved to archive",
log->PathName().c_str());
}
}
return s;
}
Status WalManager::GetUpdatesSince(
SequenceNumber seq, std::unique_ptr<TransactionLogIterator>* iter,
const TransactionLogIterator::ReadOptions& read_options,
VersionSet* version_set) {
// Get all sorted Wal Files.
// Do binary search and open files and find the seq number.
std::unique_ptr<VectorLogPtr> wal_files(new VectorLogPtr);
Status s = GetSortedWalFiles(*wal_files);
if (!s.ok()) {
return s;
}
s = RetainProbableWalFiles(*wal_files, seq);
if (!s.ok()) {
return s;
}
iter->reset(new TransactionLogIteratorImpl(
db_options_.wal_dir, &db_options_, read_options, file_options_, seq,
std::move(wal_files), version_set, seq_per_batch_));
return (*iter)->status();
}
// 1. Go through all archived files and
// a. if ttl is enabled, delete outdated files
// b. if archive size limit is enabled, delete empty files,
// compute file number and size.
// 2. If size limit is enabled:
// a. compute how many files should be deleted
// b. get sorted non-empty archived logs
// c. delete what should be deleted
void WalManager::PurgeObsoleteWALFiles() {
bool const ttl_enabled = db_options_.wal_ttl_seconds > 0;
bool const size_limit_enabled = db_options_.wal_size_limit_mb > 0;
if (!ttl_enabled && !size_limit_enabled) {
return;
}
int64_t current_time;
Status s = env_->GetCurrentTime(¤t_time);
if (!s.ok()) {
ROCKS_LOG_ERROR(db_options_.info_log, "Can't get current time: %s",
s.ToString().c_str());
assert(false);
return;
}
uint64_t const now_seconds = static_cast<uint64_t>(current_time);
uint64_t const time_to_check = (ttl_enabled && !size_limit_enabled)
? db_options_.wal_ttl_seconds / 2
: kDefaultIntervalToDeleteObsoleteWAL;
if (purge_wal_files_last_run_ + time_to_check > now_seconds) {
return;
}
purge_wal_files_last_run_ = now_seconds;
std::string archival_dir = ArchivalDirectory(db_options_.wal_dir);
std::vector<std::string> files;
s = env_->GetChildren(archival_dir, &files);
if (!s.ok()) {
ROCKS_LOG_ERROR(db_options_.info_log, "Can't get archive files: %s",
s.ToString().c_str());
assert(false);
return;
}
size_t log_files_num = 0;
uint64_t log_file_size = 0;
for (auto& f : files) {
uint64_t number;
FileType type;
if (ParseFileName(f, &number, &type) && type == kLogFile) {
std::string const file_path = archival_dir + "/" + f;
if (ttl_enabled) {
uint64_t file_m_time;
s = env_->GetFileModificationTime(file_path, &file_m_time);
if (!s.ok()) {
ROCKS_LOG_WARN(db_options_.info_log,
"Can't get file mod time: %s: %s", file_path.c_str(),
s.ToString().c_str());
continue;
}
if (now_seconds - file_m_time > db_options_.wal_ttl_seconds) {
s = DeleteDBFile(&db_options_, file_path, archival_dir, false,
/*force_fg=*/!wal_in_db_path_);
if (!s.ok()) {
ROCKS_LOG_WARN(db_options_.info_log, "Can't delete file: %s: %s",
file_path.c_str(), s.ToString().c_str());
continue;
} else {
MutexLock l(&read_first_record_cache_mutex_);
read_first_record_cache_.erase(number);
}
continue;
}
}
if (size_limit_enabled) {
uint64_t file_size;
s = env_->GetFileSize(file_path, &file_size);
if (!s.ok()) {
ROCKS_LOG_ERROR(db_options_.info_log,
"Unable to get file size: %s: %s", file_path.c_str(),
s.ToString().c_str());
return;
} else {
if (file_size > 0) {
log_file_size = std::max(log_file_size, file_size);
++log_files_num;
} else {
s = DeleteDBFile(&db_options_, file_path, archival_dir, false,
/*force_fg=*/!wal_in_db_path_);
if (!s.ok()) {
ROCKS_LOG_WARN(db_options_.info_log,
"Unable to delete file: %s: %s", file_path.c_str(),
s.ToString().c_str());
continue;
} else {
MutexLock l(&read_first_record_cache_mutex_);
read_first_record_cache_.erase(number);
}
}
}
}
}
}
if (0 == log_files_num || !size_limit_enabled) {
return;
}
size_t const files_keep_num =
static_cast<size_t>(db_options_.wal_size_limit_mb * 1024 * 1024 / log_file_size);
if (log_files_num <= files_keep_num) {
return;
}
size_t files_del_num = log_files_num - files_keep_num;
VectorLogPtr archived_logs;
GetSortedWalsOfType(archival_dir, archived_logs, kArchivedLogFile);
if (files_del_num > archived_logs.size()) {
ROCKS_LOG_WARN(db_options_.info_log,
"Trying to delete more archived log files than "
"exist. Deleting all");
files_del_num = archived_logs.size();
}
for (size_t i = 0; i < files_del_num; ++i) {
std::string const file_path = archived_logs[i]->PathName();
s = DeleteDBFile(&db_options_, db_options_.wal_dir + "/" + file_path,
db_options_.wal_dir, false,
/*force_fg=*/!wal_in_db_path_);
if (!s.ok()) {
ROCKS_LOG_WARN(db_options_.info_log, "Unable to delete file: %s: %s",
file_path.c_str(), s.ToString().c_str());
continue;
} else {
MutexLock l(&read_first_record_cache_mutex_);
read_first_record_cache_.erase(archived_logs[i]->LogNumber());
}
}
}
void WalManager::ArchiveWALFile(const std::string& fname, uint64_t number) {
auto archived_log_name = ArchivedLogFileName(db_options_.wal_dir, number);
// The sync point below is used in (DBTest,TransactionLogIteratorRace)
TEST_SYNC_POINT("WalManager::PurgeObsoleteFiles:1");
Status s = env_->RenameFile(fname, archived_log_name);
// The sync point below is used in (DBTest,TransactionLogIteratorRace)
TEST_SYNC_POINT("WalManager::PurgeObsoleteFiles:2");
ROCKS_LOG_INFO(db_options_.info_log, "Move log file %s to %s -- %s\n",
fname.c_str(), archived_log_name.c_str(),
s.ToString().c_str());
}
Status WalManager::GetSortedWalsOfType(const std::string& path,
VectorLogPtr& log_files,
WalFileType log_type) {
std::vector<std::string> all_files;
const Status status = env_->GetChildren(path, &all_files);
if (!status.ok()) {
return status;
}
log_files.reserve(all_files.size());
for (const auto& f : all_files) {
uint64_t number;
FileType type;
if (ParseFileName(f, &number, &type) && type == kLogFile) {
SequenceNumber sequence;
Status s = ReadFirstRecord(log_type, number, &sequence);
if (!s.ok()) {
return s;
}
if (sequence == 0) {
// empty file
continue;
}
// Reproduce the race condition where a log file is moved
// to archived dir, between these two sync points, used in
// (DBTest,TransactionLogIteratorRace)
TEST_SYNC_POINT("WalManager::GetSortedWalsOfType:1");
TEST_SYNC_POINT("WalManager::GetSortedWalsOfType:2");
uint64_t size_bytes;
s = env_->GetFileSize(LogFileName(path, number), &size_bytes);
// re-try in case the alive log file has been moved to archive.
if (!s.ok() && log_type == kAliveLogFile) {
std::string archived_file = ArchivedLogFileName(path, number);
if (env_->FileExists(archived_file).ok()) {
s = env_->GetFileSize(archived_file, &size_bytes);
if (!s.ok() && env_->FileExists(archived_file).IsNotFound()) {
// oops, the file just got deleted from archived dir! move on
s = Status::OK();
continue;
}
}
}
if (!s.ok()) {
return s;
}
log_files.push_back(std::unique_ptr<LogFile>(
new LogFileImpl(number, log_type, sequence, size_bytes)));
}
}
std::sort(
log_files.begin(), log_files.end(),
[](const std::unique_ptr<LogFile>& a, const std::unique_ptr<LogFile>& b) {
LogFileImpl* a_impl = static_cast_with_check<LogFileImpl>(a.get());
LogFileImpl* b_impl = static_cast_with_check<LogFileImpl>(b.get());
return *a_impl < *b_impl;
});
return status;
}
Status WalManager::RetainProbableWalFiles(VectorLogPtr& all_logs,
const SequenceNumber target) {
int64_t start = 0; // signed to avoid overflow when target is < first file.
int64_t end = static_cast<int64_t>(all_logs.size()) - 1;
// Binary Search. avoid opening all files.
while (end >= start) {
int64_t mid = start + (end - start) / 2; // Avoid overflow.
SequenceNumber current_seq_num = all_logs.at(static_cast<size_t>(mid))->StartSequence();
if (current_seq_num == target) {
end = mid;
break;
} else if (current_seq_num < target) {
start = mid + 1;
} else {
end = mid - 1;
}
}
// end could be -ve.
size_t start_index = static_cast<size_t>(std::max(static_cast<int64_t>(0), end));
// The last wal file is always included
all_logs.erase(all_logs.begin(), all_logs.begin() + start_index);
return Status::OK();
}
Status WalManager::ReadFirstRecord(const WalFileType type,
const uint64_t number,
SequenceNumber* sequence) {
*sequence = 0;
if (type != kAliveLogFile && type != kArchivedLogFile) {
ROCKS_LOG_ERROR(db_options_.info_log, "[WalManger] Unknown file type %s",
ToString(type).c_str());
return Status::NotSupported(
"File Type Not Known " + ToString(type));
}
{
MutexLock l(&read_first_record_cache_mutex_);
auto itr = read_first_record_cache_.find(number);
if (itr != read_first_record_cache_.end()) {
*sequence = itr->second;
return Status::OK();
}
}
Status s;
if (type == kAliveLogFile) {
std::string fname = LogFileName(db_options_.wal_dir, number);
s = ReadFirstLine(fname, number, sequence);
if (!s.ok() && env_->FileExists(fname).ok()) {
// return any error that is not caused by non-existing file
return s;
}
}
if (type == kArchivedLogFile || !s.ok()) {
// check if the file got moved to archive.
std::string archived_file =
ArchivedLogFileName(db_options_.wal_dir, number);
s = ReadFirstLine(archived_file, number, sequence);
// maybe the file was deleted from archive dir. If that's the case, return
// Status::OK(). The caller with identify this as empty file because
// *sequence == 0
if (!s.ok() && env_->FileExists(archived_file).IsNotFound()) {
return Status::OK();
}
}
if (s.ok() && *sequence != 0) {
MutexLock l(&read_first_record_cache_mutex_);
read_first_record_cache_.insert({number, *sequence});
}
return s;
}
Status WalManager::GetLiveWalFile(uint64_t number,
std::unique_ptr<LogFile>* log_file) {
if (!log_file) {
return Status::InvalidArgument("log_file not preallocated.");
}
if (!number) {
return Status::PathNotFound("log file not available");
}
Status s;
uint64_t size_bytes;
s = env_->GetFileSize(LogFileName(db_options_.wal_dir, number), &size_bytes);
if (!s.ok()) {
return s;
}
log_file->reset(new LogFileImpl(number, kAliveLogFile,
0, // SequenceNumber
size_bytes));
return Status::OK();
}
// the function returns status.ok() and sequence == 0 if the file exists, but is
// empty
Status WalManager::ReadFirstLine(const std::string& fname,
const uint64_t number,
SequenceNumber* sequence) {
struct LogReporter : public log::Reader::Reporter {
Env* env;
Logger* info_log;
const char* fname;
Status* status;
bool ignore_error; // true if db_options_.paranoid_checks==false
void Corruption(size_t bytes, const Status& s) override {
ROCKS_LOG_WARN(info_log, "[WalManager] %s%s: dropping %d bytes; %s",
(this->ignore_error ? "(ignoring error) " : ""), fname,
static_cast<int>(bytes), s.ToString().c_str());
if (this->status->ok()) {
// only keep the first error
*this->status = s;
}
}
};
std::unique_ptr<FSSequentialFile> file;
Status status = fs_->NewSequentialFile(fname,
fs_->OptimizeForLogRead(file_options_),
&file, nullptr);
std::unique_ptr<SequentialFileReader> file_reader(
new SequentialFileReader(std::move(file), fname));
if (!status.ok()) {
return status;
}
LogReporter reporter;
reporter.env = env_;
reporter.info_log = db_options_.info_log.get();
reporter.fname = fname.c_str();
reporter.status = &status;
reporter.ignore_error = !db_options_.paranoid_checks;
log::Reader reader(db_options_.info_log, std::move(file_reader), &reporter,
true /*checksum*/, number);
std::string scratch;
Slice record;
if (reader.ReadRecord(&record, &scratch) &&
(status.ok() || !db_options_.paranoid_checks)) {
if (record.size() < WriteBatchInternal::kHeader) {
reporter.Corruption(record.size(),
Status::Corruption("log record too small"));
// TODO read record's till the first no corrupt entry?
} else {
WriteBatch batch;
WriteBatchInternal::SetContents(&batch, record);
*sequence = WriteBatchInternal::Sequence(&batch);
return Status::OK();
}
}
// ReadRecord returns false on EOF, which means that the log file is empty. we
// return status.ok() in that case and set sequence number to 0
*sequence = 0;
return status;
}
#endif // ROCKSDB_LITE
} // namespace ROCKSDB_NAMESPACE
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