3ebb7ba7b9
Summary: Changing blob file format and some code cleanup around the change. The change with blob log format are: * Remove timestamp field in blob file header, blob file footer and blob records. The field is not being use and often confuse with expiration field. * Blob file header now come with column family id, which always equal to default column family id. It leaves room for future support of column family. * Compression field in blob file header now is a standalone byte (instead of compact encode with flags field) * Blob file footer now come with its own crc. * Key length now being uint64_t instead of uint32_t * Blob CRC now checksum both key and value (instead of value only). * Some reordering of the fields. The list of cleanups: * Better inline comments in blob_log_format.h * rename ttlrange_t and snrange_t to ExpirationRange and SequenceRange respectively. * simplify blob_db::Reader * Move crc checking logic to inside blob_log_format.cc Closes https://github.com/facebook/rocksdb/pull/3081 Differential Revision: D6171304 Pulled By: yiwu-arbug fbshipit-source-id: e4373e0d39264441b7e2fbd0caba93ddd99ea2af
92 lines
2.6 KiB
C++
92 lines
2.6 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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#pragma once
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#ifndef ROCKSDB_LITE
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#include <cstdint>
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#include <memory>
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#include <string>
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#include "rocksdb/slice.h"
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#include "rocksdb/status.h"
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#include "rocksdb/types.h"
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#include "utilities/blob_db/blob_log_format.h"
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namespace rocksdb {
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class WritableFileWriter;
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namespace blob_db {
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/**
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* Writer is the blob log stream writer. It provides an append-only
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* abstraction for writing blob data.
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*
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*
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* Look at blob_db_format.h to see the details of the record formats.
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*/
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class Writer {
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public:
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// Create a writer that will append data to "*dest".
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// "*dest" must be initially empty.
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// "*dest" must remain live while this Writer is in use.
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explicit Writer(std::unique_ptr<WritableFileWriter>&& dest,
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uint64_t log_number, uint64_t bpsync, bool use_fsync,
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uint64_t boffset = 0);
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~Writer() = default;
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// No copying allowed
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Writer(const Writer&) = delete;
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Writer& operator=(const Writer&) = delete;
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static void ConstructBlobHeader(std::string* buf, const Slice& key,
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const Slice& val, uint64_t expiration);
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Status AddRecord(const Slice& key, const Slice& val, uint64_t* key_offset,
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uint64_t* blob_offset);
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Status AddRecord(const Slice& key, const Slice& val, uint64_t expiration,
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uint64_t* key_offset, uint64_t* blob_offset);
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Status EmitPhysicalRecord(const std::string& headerbuf, const Slice& key,
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const Slice& val, uint64_t* key_offset,
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uint64_t* blob_offset);
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Status AppendFooter(BlobLogFooter& footer);
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Status WriteHeader(BlobLogHeader& header);
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WritableFileWriter* file() { return dest_.get(); }
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const WritableFileWriter* file() const { return dest_.get(); }
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uint64_t get_log_number() const { return log_number_; }
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bool ShouldSync() const { return block_offset_ > next_sync_offset_; }
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void Sync();
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void ResetSyncPointer() { next_sync_offset_ += bytes_per_sync_; }
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private:
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std::unique_ptr<WritableFileWriter> dest_;
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uint64_t log_number_;
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uint64_t block_offset_; // Current offset in block
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uint64_t bytes_per_sync_;
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uint64_t next_sync_offset_;
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bool use_fsync_;
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public:
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enum ElemType { kEtNone, kEtFileHdr, kEtRecord, kEtFileFooter };
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ElemType last_elem_type_;
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};
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} // namespace blob_db
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} // namespace rocksdb
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#endif // ROCKSDB_LITE
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