mirror of
https://github.com/facebook/rocksdb.git
synced 2024-11-27 02:44:18 +00:00
78279350aa
Summary: Adding a list of blob db counters. Also remove WaStats() which doesn't expose the stats and can be substitute by (BLOB_DB_BYTES_WRITTEN / BLOB_DB_BLOB_FILE_BYTES_WRITTEN). Closes https://github.com/facebook/rocksdb/pull/3193 Differential Revision: D6394216 Pulled By: yiwu-arbug fbshipit-source-id: 017508c8ff3fcd7ea7403c64d0f9834b24816803
83 lines
2.3 KiB
C++
83 lines
2.3 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).
|
|
//
|
|
#pragma once
|
|
|
|
#ifndef ROCKSDB_LITE
|
|
|
|
#include <memory>
|
|
#include <string>
|
|
|
|
#include "rocksdb/env.h"
|
|
#include "rocksdb/slice.h"
|
|
#include "rocksdb/statistics.h"
|
|
#include "rocksdb/status.h"
|
|
#include "utilities/blob_db/blob_log_format.h"
|
|
|
|
namespace rocksdb {
|
|
|
|
class SequentialFileReader;
|
|
class Logger;
|
|
|
|
namespace blob_db {
|
|
|
|
/**
|
|
* Reader is a general purpose log stream reader implementation. The actual job
|
|
* of reading from the device is implemented by the SequentialFile interface.
|
|
*
|
|
* Please see Writer for details on the file and record layout.
|
|
*/
|
|
class Reader {
|
|
public:
|
|
enum ReadLevel {
|
|
kReadHeader,
|
|
kReadHeaderKey,
|
|
kReadHeaderKeyBlob,
|
|
};
|
|
|
|
// Create a reader that will return log records from "*file".
|
|
// "*file" must remain live while this Reader is in use.
|
|
Reader(std::unique_ptr<SequentialFileReader>&& file_reader, Env* env,
|
|
Statistics* statistics);
|
|
|
|
~Reader() = default;
|
|
|
|
// No copying allowed
|
|
Reader(const Reader&) = delete;
|
|
Reader& operator=(const Reader&) = delete;
|
|
|
|
Status ReadHeader(BlobLogHeader* header);
|
|
|
|
// Read the next record into *record. Returns true if read
|
|
// successfully, false if we hit end of the input. May use
|
|
// "*scratch" as temporary storage. The contents filled in *record
|
|
// will only be valid until the next mutating operation on this
|
|
// reader or the next mutation to *scratch.
|
|
// If blob_offset is non-null, return offset of the blob through it.
|
|
Status ReadRecord(BlobLogRecord* record, ReadLevel level = kReadHeader,
|
|
uint64_t* blob_offset = nullptr);
|
|
|
|
Status ReadSlice(uint64_t size, Slice* slice, std::string* buf);
|
|
|
|
void ResetNextByte() { next_byte_ = 0; }
|
|
|
|
uint64_t GetNextByte() const { return next_byte_; }
|
|
|
|
private:
|
|
const std::unique_ptr<SequentialFileReader> file_;
|
|
Env* env_;
|
|
Statistics* statistics_;
|
|
|
|
std::string backing_store_;
|
|
Slice buffer_;
|
|
|
|
// which byte to read next. For asserting proper usage
|
|
uint64_t next_byte_;
|
|
};
|
|
|
|
} // namespace blob_db
|
|
} // namespace rocksdb
|
|
#endif // ROCKSDB_LITE
|