1b7c4ce89d
(Based on a suggestion by cmumford.) "open" benchmark on my workstation speeds up significantly since we can now avoid three fdatasync calls and a compaction per open: Before: ~80000 microseconds After: ~130 microseconds Details: (1) Added Options::reuse_logs (currently defaults to false) to control new behavior. The intention is to change the default to true after some baking. (2) Added Env::NewAppendableFile() whose default implementation returns a not-supported error. (3) VersionSet::Recovery attempts to reuse the MANIFEST from which it is recovering. (4) DBImpl recovery attempts to reuse the last log file and memtable. (5) db_test.cc now tests a new configuration that sets reuse_logs to true. (6) fault_injection_test also tests a reuse_logs==true config. (7) Added a new recovery_test.
55 lines
1.5 KiB
C++
55 lines
1.5 KiB
C++
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#ifndef STORAGE_LEVELDB_DB_LOG_WRITER_H_
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#define STORAGE_LEVELDB_DB_LOG_WRITER_H_
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#include <stdint.h>
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#include "db/log_format.h"
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#include "leveldb/slice.h"
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#include "leveldb/status.h"
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namespace leveldb {
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class WritableFile;
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namespace log {
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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(WritableFile* dest);
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// Create a writer that will append data to "*dest".
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// "*dest" must have initial length "dest_length".
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// "*dest" must remain live while this Writer is in use.
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Writer(WritableFile* dest, uint64_t dest_length);
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~Writer();
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Status AddRecord(const Slice& slice);
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private:
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WritableFile* dest_;
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int block_offset_; // Current offset in block
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// crc32c values for all supported record types. These are
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// pre-computed to reduce the overhead of computing the crc of the
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// record type stored in the header.
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uint32_t type_crc_[kMaxRecordType + 1];
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Status EmitPhysicalRecord(RecordType type, const char* ptr, size_t length);
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// No copying allowed
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Writer(const Writer&);
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void operator=(const Writer&);
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};
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} // namespace log
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} // namespace leveldb
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#endif // STORAGE_LEVELDB_DB_LOG_WRITER_H_
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