rocksdb/db/wal_manager.cc
Andrew Kryczka d7242ff4d5 Fix GetSortedWalFiles when log recycling enabled
Summary:
Previously the sequence number was mistakenly passed in an argument
where the log number should go. This caused the reader to assume the old WAL
format was used, which is incompatible with the WAL recycling format.

Test Plan:
new unit test, verified it fails before this change and passes
afterwards.

Reviewers: yiwu, lightmark, IslamAbdelRahman, sdong

Reviewed By: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D63987
2016-09-15 09:55:02 -07:00

479 lines
16 KiB
C++

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "db/wal_manager.h"
#ifndef __STDC_FORMAT_MACROS
#define __STDC_FORMAT_MACROS
#endif
#include <inttypes.h>
#include <algorithm>
#include <vector>
#include <memory>
#include "db/filename.h"
#include "db/transaction_log_impl.h"
#include "db/log_reader.h"
#include "db/log_writer.h"
#include "db/write_batch_internal.h"
#include "port/port.h"
#include "rocksdb/env.h"
#include "rocksdb/options.h"
#include "rocksdb/write_batch.h"
#include "util/coding.h"
#include "util/file_reader_writer.h"
#include "util/logging.h"
#include "util/mutexlock.h"
#include "util/sync_point.h"
#include "util/string_util.h"
namespace rocksdb {
#ifndef ROCKSDB_LITE
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();
Log(InfoLogLevel::INFO_LEVEL, 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.
Log(InfoLogLevel::WARN_LEVEL, 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, env_options_, seq,
std::move(wal_files), version_set));
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(&current_time);
if (!s.ok()) {
Log(InfoLogLevel::ERROR_LEVEL, 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()) {
Log(InfoLogLevel::ERROR_LEVEL, 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()) {
Log(InfoLogLevel::WARN_LEVEL, 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 = env_->DeleteFile(file_path);
if (!s.ok()) {
Log(InfoLogLevel::WARN_LEVEL, 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()) {
Log(InfoLogLevel::ERROR_LEVEL, 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 = env_->DeleteFile(file_path);
if (!s.ok()) {
Log(InfoLogLevel::WARN_LEVEL, 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 =
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()) {
Log(InfoLogLevel::WARN_LEVEL, 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 = env_->DeleteFile(db_options_.wal_dir + "/" + file_path);
if (!s.ok()) {
Log(InfoLogLevel::WARN_LEVEL, 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");
Log(InfoLogLevel::INFO_LEVEL, db_options_.info_log,
"Move log file %s to %s -- %s\n", fname.c_str(),
archived_log_name.c_str(), s.ToString().c_str());
}
namespace {
struct CompareLogByPointer {
bool operator()(const std::unique_ptr<LogFile>& a,
const std::unique_ptr<LogFile>& b) {
LogFileImpl* a_impl = dynamic_cast<LogFileImpl*>(a.get());
LogFileImpl* b_impl = dynamic_cast<LogFileImpl*>(b.get());
return *a_impl < *b_impl;
}
};
}
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.
std::string archived_file = ArchivedLogFileName(path, number);
if (!s.ok() && log_type == kAliveLogFile &&
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)));
}
}
CompareLogByPointer compare_log_files;
std::sort(log_files.begin(), log_files.end(), compare_log_files);
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(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 = 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) {
Log(InfoLogLevel::ERROR_LEVEL, 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 (env_->FileExists(fname).ok() && !s.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;
}
// 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
virtual void Corruption(size_t bytes, const Status& s) override {
Log(InfoLogLevel::WARN_LEVEL, 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<SequentialFile> file;
Status status = env_->NewSequentialFile(fname, &file, env_options_);
unique_ptr<SequentialFileReader> file_reader(
new SequentialFileReader(std::move(file)));
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*/, 0 /*initial_offset*/, 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