rocksdb/utilities/blob_db/blob_log_reader.cc
Yi Wu 0552029b5c Blob DB: not writing sequence number as blob record footer
Summary:
Previously each time we write a blob we write blog_record_header + key + value + blob_record_footer to blob log. The footer only contains a sequence and a crc for the sequence number. The sequence number was used in garbage collection to verify the value is recent. After #2703 we moved to use optimistic transaction and no longer use sequence number from the footer. Remove the footer altogether.

There's another usage of sequence number and we are keeping it: Each blob log file keep track of sequence number range of keys in it, and use it to check if it is reference by a snapshot, before being deleted.
Closes https://github.com/facebook/rocksdb/pull/3005

Differential Revision: D6057585

Pulled By: yiwu-arbug

fbshipit-source-id: d6da53c457a316e9723f359a1b47facfc3ffe090
2017-10-17 12:13:08 -07:00

135 lines
4.3 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_log_reader.h"
#include <cstdio>
#include "rocksdb/env.h"
#include "util/coding.h"
#include "util/crc32c.h"
#include "util/file_reader_writer.h"
namespace rocksdb {
namespace blob_db {
Reader::Reader(std::shared_ptr<Logger> info_log,
unique_ptr<SequentialFileReader>&& _file)
: info_log_(info_log), file_(std::move(_file)), buffer_(), next_byte_(0) {
backing_store_.resize(kBlockSize);
}
Reader::~Reader() {}
Status Reader::ReadHeader(BlobLogHeader* header) {
assert(file_.get() != nullptr);
assert(next_byte_ == 0);
Status status =
file_->Read(BlobLogHeader::kHeaderSize, &buffer_, GetReadBuffer());
next_byte_ += buffer_.size();
if (!status.ok()) return status;
if (buffer_.size() != BlobLogHeader::kHeaderSize) {
return Status::IOError("EOF reached before file header");
}
status = header->DecodeFrom(buffer_);
return status;
}
Status Reader::ReadRecord(BlobLogRecord* record, ReadLevel level,
uint64_t* blob_offset) {
record->Clear();
buffer_.clear();
backing_store_[0] = '\0';
Status status =
file_->Read(BlobLogRecord::kHeaderSize, &buffer_, GetReadBuffer());
next_byte_ += buffer_.size();
if (!status.ok()) return status;
if (buffer_.size() != BlobLogRecord::kHeaderSize) {
return Status::IOError("EOF reached before record header");
}
status = record->DecodeHeaderFrom(buffer_);
if (!status.ok()) {
return status;
}
uint32_t header_crc = 0;
uint32_t blob_crc = 0;
size_t crc_data_size = BlobLogRecord::kHeaderSize - 2 * sizeof(uint32_t);
header_crc = crc32c::Extend(header_crc, buffer_.data(), crc_data_size);
uint64_t kb_size = record->GetKeySize() + record->GetBlobSize();
if (blob_offset != nullptr) {
*blob_offset = next_byte_ + record->GetKeySize();
}
switch (level) {
case kReadHeader:
file_->Skip(kb_size);
next_byte_ += kb_size;
case kReadHeaderKey:
record->ResizeKeyBuffer(record->GetKeySize());
status = file_->Read(record->GetKeySize(), &record->key_,
record->GetKeyBuffer());
next_byte_ += record->key_.size();
if (!status.ok()) return status;
if (record->key_.size() != record->GetKeySize()) {
return Status::IOError("EOF reached before key read");
}
header_crc =
crc32c::Extend(header_crc, record->key_.data(), record->GetKeySize());
header_crc = crc32c::Mask(header_crc);
if (header_crc != record->header_cksum_) {
return Status::Corruption("Record Checksum mismatch: header_cksum");
}
file_->Skip(record->GetBlobSize());
next_byte_ += record->GetBlobSize();
case kReadHeaderKeyBlob:
record->ResizeKeyBuffer(record->GetKeySize());
status = file_->Read(record->GetKeySize(), &record->key_,
record->GetKeyBuffer());
next_byte_ += record->key_.size();
if (!status.ok()) return status;
if (record->key_.size() != record->GetKeySize()) {
return Status::IOError("EOF reached before key read");
}
header_crc =
crc32c::Extend(header_crc, record->key_.data(), record->GetKeySize());
header_crc = crc32c::Mask(header_crc);
if (header_crc != record->header_cksum_) {
return Status::Corruption("Record Checksum mismatch: header_cksum");
}
record->ResizeBlobBuffer(record->GetBlobSize());
status = file_->Read(record->GetBlobSize(), &record->blob_,
record->GetBlobBuffer());
next_byte_ += record->blob_.size();
if (!status.ok()) return status;
if (record->blob_.size() != record->GetBlobSize()) {
return Status::IOError("EOF reached during blob read");
}
blob_crc =
crc32c::Extend(blob_crc, record->blob_.data(), record->blob_.size());
blob_crc = crc32c::Mask(blob_crc);
if (blob_crc != record->checksum_) {
return Status::Corruption("Blob Checksum mismatch");
}
}
return status;
}
} // namespace blob_db
} // namespace rocksdb
#endif // ROCKSDB_LITE