rocksdb/utilities/blob_db/blob_file.cc
Yi Wu 237b292515 BlobDB: Remove the need to get sequence number per write
Summary:
Previously we store sequence number range of each blob files, and use the sequence number range to check if the file can be possibly visible by a snapshot. But it adds complexity to the code, since the sequence number is only available after a write. (The current implementation get sequence number by calling GetLatestSequenceNumber(), which is wrong.) With the patch, we are not storing sequence number range, and check if snapshot_sequence < obsolete_sequence to decide if the file is visible by a snapshot (previously we check if first_sequence <= snapshot_sequence < obsolete_sequence).
Closes https://github.com/facebook/rocksdb/pull/3274

Differential Revision: D6571497

Pulled By: yiwu-arbug

fbshipit-source-id: ca06479dc1fcd8782f6525b62b7762cd47d61909
2017-12-15 13:27:30 -08:00

332 lines
9.8 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 "utilities/blob_db/blob_file.h"
#ifndef __STDC_FORMAT_MACROS
#define __STDC_FORMAT_MACROS
#endif
#include <inttypes.h>
#include <stdio.h>
#include <algorithm>
#include <limits>
#include <memory>
#include "db/column_family.h"
#include "db/db_impl.h"
#include "db/dbformat.h"
#include "util/filename.h"
#include "util/logging.h"
#include "utilities/blob_db/blob_db_impl.h"
namespace rocksdb {
namespace blob_db {
BlobFile::BlobFile()
: parent_(nullptr),
file_number_(0),
info_log_(nullptr),
column_family_id_(std::numeric_limits<uint32_t>::max()),
compression_(kNoCompression),
has_ttl_(false),
blob_count_(0),
gc_epoch_(-1),
file_size_(0),
deleted_count_(0),
deleted_size_(0),
closed_(false),
obsolete_(false),
gc_once_after_open_(false),
expiration_range_({0, 0}),
last_access_(-1),
last_fsync_(0),
header_valid_(false),
footer_valid_(false) {}
BlobFile::BlobFile(const BlobDBImpl* p, const std::string& bdir, uint64_t fn,
Logger* info_log)
: parent_(p),
path_to_dir_(bdir),
file_number_(fn),
info_log_(info_log),
column_family_id_(std::numeric_limits<uint32_t>::max()),
compression_(kNoCompression),
has_ttl_(false),
blob_count_(0),
gc_epoch_(-1),
file_size_(0),
deleted_count_(0),
deleted_size_(0),
closed_(false),
obsolete_(false),
gc_once_after_open_(false),
expiration_range_({0, 0}),
last_access_(-1),
last_fsync_(0),
header_valid_(false),
footer_valid_(false) {}
BlobFile::~BlobFile() {
if (obsolete_) {
std::string pn(PathName());
Status s = Env::Default()->DeleteFile(PathName());
if (!s.ok()) {
// ROCKS_LOG_INFO(db_options_.info_log,
// "File could not be deleted %s", pn.c_str());
}
}
}
uint32_t BlobFile::column_family_id() const { return column_family_id_; }
std::string BlobFile::PathName() const {
return BlobFileName(path_to_dir_, file_number_);
}
std::shared_ptr<Reader> BlobFile::OpenSequentialReader(
Env* env, const DBOptions& db_options,
const EnvOptions& env_options) const {
std::unique_ptr<SequentialFile> sfile;
Status s = env->NewSequentialFile(PathName(), &sfile, env_options);
if (!s.ok()) {
// report something here.
return nullptr;
}
std::unique_ptr<SequentialFileReader> sfile_reader;
sfile_reader.reset(new SequentialFileReader(std::move(sfile)));
std::shared_ptr<Reader> log_reader = std::make_shared<Reader>(
std::move(sfile_reader), db_options.env, db_options.statistics.get());
return log_reader;
}
std::string BlobFile::DumpState() const {
char str[1000];
snprintf(str, sizeof(str),
"path: %s fn: %" PRIu64 " blob_count: %" PRIu64 " gc_epoch: %" PRIu64
" file_size: %" PRIu64 " deleted_count: %" PRIu64
" deleted_size: %" PRIu64
" closed: %d obsolete: %d expiration_range: (%" PRIu64 ", %" PRIu64
"), writer: %d reader: %d",
path_to_dir_.c_str(), file_number_, blob_count_.load(),
gc_epoch_.load(), file_size_.load(), deleted_count_, deleted_size_,
closed_.load(), obsolete_.load(), expiration_range_.first,
expiration_range_.second, (!!log_writer_), (!!ra_file_reader_));
return str;
}
void BlobFile::MarkObsolete(SequenceNumber sequence) {
assert(Immutable());
obsolete_sequence_ = sequence;
obsolete_.store(true);
}
bool BlobFile::NeedsFsync(bool hard, uint64_t bytes_per_sync) const {
assert(last_fsync_ <= file_size_);
return (hard) ? file_size_ > last_fsync_
: (file_size_ - last_fsync_) >= bytes_per_sync;
}
Status BlobFile::WriteFooterAndCloseLocked() {
BlobLogFooter footer;
footer.blob_count = blob_count_;
if (HasTTL()) {
footer.expiration_range = expiration_range_;
}
// this will close the file and reset the Writable File Pointer.
Status s = log_writer_->AppendFooter(footer);
if (s.ok()) {
closed_ = true;
file_size_ += BlobLogFooter::kSize;
}
// delete the sequential writer
log_writer_.reset();
return s;
}
Status BlobFile::ReadFooter(BlobLogFooter* bf) {
if (file_size_ < (BlobLogHeader::kSize + BlobLogFooter::kSize)) {
return Status::IOError("File does not have footer", PathName());
}
uint64_t footer_offset = file_size_ - BlobLogFooter::kSize;
// assume that ra_file_reader_ is valid before we enter this
assert(ra_file_reader_);
Slice result;
char scratch[BlobLogFooter::kSize + 10];
Status s = ra_file_reader_->Read(footer_offset, BlobLogFooter::kSize, &result,
scratch);
if (!s.ok()) return s;
if (result.size() != BlobLogFooter::kSize) {
// should not happen
return Status::IOError("EOF reached before footer");
}
s = bf->DecodeFrom(result);
return s;
}
Status BlobFile::SetFromFooterLocked(const BlobLogFooter& footer) {
// assume that file has been fully fsync'd
last_fsync_.store(file_size_);
blob_count_ = footer.blob_count;
expiration_range_ = footer.expiration_range;
closed_ = true;
return Status::OK();
}
Status BlobFile::Fsync() {
Status s;
if (log_writer_.get()) {
s = log_writer_->Sync();
last_fsync_.store(file_size_.load());
}
return s;
}
void BlobFile::CloseRandomAccessLocked() {
ra_file_reader_.reset();
last_access_ = -1;
}
std::shared_ptr<RandomAccessFileReader> BlobFile::GetOrOpenRandomAccessReader(
Env* env, const EnvOptions& env_options, bool* fresh_open) {
*fresh_open = false;
int64_t current_time = 0;
env->GetCurrentTime(&current_time);
last_access_.store(current_time);
{
ReadLock lockbfile_r(&mutex_);
if (ra_file_reader_) return ra_file_reader_;
}
WriteLock lockbfile_w(&mutex_);
if (ra_file_reader_) return ra_file_reader_;
std::unique_ptr<RandomAccessFile> rfile;
Status s = env->NewRandomAccessFile(PathName(), &rfile, env_options);
if (!s.ok()) {
ROCKS_LOG_ERROR(info_log_,
"Failed to open blob file for random-read: %s status: '%s'"
" exists: '%s'",
PathName().c_str(), s.ToString().c_str(),
env->FileExists(PathName()).ToString().c_str());
return nullptr;
}
ra_file_reader_ = std::make_shared<RandomAccessFileReader>(std::move(rfile),
PathName());
*fresh_open = true;
return ra_file_reader_;
}
Status BlobFile::ReadMetadata(Env* env, const EnvOptions& env_options) {
assert(Immutable());
// Get file size.
uint64_t file_size = 0;
Status s = env->GetFileSize(PathName(), &file_size);
if (s.ok()) {
file_size_ = file_size;
} else {
ROCKS_LOG_ERROR(info_log_,
"Failed to get size of blob file %" ROCKSDB_PRIszt
", status: %s",
file_number_, s.ToString().c_str());
return s;
}
if (file_size < BlobLogHeader::kSize) {
ROCKS_LOG_ERROR(info_log_,
"Incomplete blob file blob file %" ROCKSDB_PRIszt
", size: %" PRIu64,
file_number_, file_size);
return Status::Corruption("Incomplete blob file header.");
}
// Create file reader.
std::unique_ptr<RandomAccessFile> file;
s = env->NewRandomAccessFile(PathName(), &file, env_options);
if (!s.ok()) {
ROCKS_LOG_ERROR(info_log_,
"Failed to open blob file %" ROCKSDB_PRIszt ", status: %s",
file_number_, s.ToString().c_str());
return s;
}
std::unique_ptr<RandomAccessFileReader> file_reader(
new RandomAccessFileReader(std::move(file), PathName()));
// Read file header.
char header_buf[BlobLogHeader::kSize];
Slice header_slice;
s = file_reader->Read(0, BlobLogHeader::kSize, &header_slice, header_buf);
if (!s.ok()) {
ROCKS_LOG_ERROR(info_log_,
"Failed to read header of blob file %" ROCKSDB_PRIszt
", status: %s",
file_number_, s.ToString().c_str());
return s;
}
BlobLogHeader header;
s = header.DecodeFrom(header_slice);
if (!s.ok()) {
ROCKS_LOG_ERROR(info_log_,
"Failed to decode header of blob file %" ROCKSDB_PRIszt
", status: %s",
file_number_, s.ToString().c_str());
return s;
}
column_family_id_ = header.column_family_id;
compression_ = header.compression;
has_ttl_ = header.has_ttl;
if (has_ttl_) {
expiration_range_ = header.expiration_range;
}
header_valid_ = true;
// Read file footer.
if (file_size_ < BlobLogHeader::kSize + BlobLogFooter::kSize) {
// OK not to have footer.
assert(!footer_valid_);
return Status::OK();
}
char footer_buf[BlobLogFooter::kSize];
Slice footer_slice;
s = file_reader->Read(file_size - BlobLogFooter::kSize, BlobLogFooter::kSize,
&footer_slice, footer_buf);
if (!s.ok()) {
ROCKS_LOG_ERROR(info_log_,
"Failed to read footer of blob file %" ROCKSDB_PRIszt
", status: %s",
file_number_, s.ToString().c_str());
return s;
}
BlobLogFooter footer;
s = footer.DecodeFrom(footer_slice);
if (!s.ok()) {
// OK not to have footer.
assert(!footer_valid_);
return Status::OK();
}
blob_count_ = footer.blob_count;
if (has_ttl_) {
assert(header.expiration_range.first <= footer.expiration_range.first);
assert(header.expiration_range.second >= footer.expiration_range.second);
expiration_range_ = footer.expiration_range;
}
footer_valid_ = true;
return Status::OK();
}
} // namespace blob_db
} // namespace rocksdb
#endif // ROCKSDB_LITE