250a51a3f9
Summary: Refactor BlobDB open logic. List of changes: Major: * On reopen, mark blob files found as immutable, do not use them for writing new keys. * Not to scan the whole file to find file footer. Instead just seek to the end of the file and try to read footer. Minor: * Move most of the real logic from blob_db.cc to blob_db_impl.cc. * Not to hold shared_ptr of event listeners in global maps in blob_db.cc * Some changes to BlobFile interface. * Improve logging and error handling. Closes https://github.com/facebook/rocksdb/pull/3246 Differential Revision: D6526147 Pulled By: yiwu-arbug fbshipit-source-id: 9dc4cdd63359a2f9b696af817086949da8d06952
96 lines
2.7 KiB
C++
96 lines
2.7 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/env.h"
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#include "rocksdb/slice.h"
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#include "rocksdb/statistics.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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Writer(std::unique_ptr<WritableFileWriter>&& dest, Env* env,
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Statistics* statistics, uint64_t log_number, uint64_t bpsync,
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bool use_fsync, 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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Status 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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Env* env_;
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Statistics* statistics_;
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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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