rocksdb/db/transaction_log_iterator_impl.h
Dhruba Borthakur ad96563b79 Ability to configure bufferedio-reads, filesystem-readaheads and mmap-read-write per database.
Summary:
This patch allows an application to specify whether to use bufferedio,
reads-via-mmaps and writes-via-mmaps per database. Earlier, there
was a global static variable that was used to configure this functionality.

The default setting remains the same (and is backward compatible):
 1. use bufferedio
 2. do not use mmaps for reads
 3. use mmap for writes
 4. use readaheads for reads needed for compaction

I also added a parameter to db_bench to be able to explicitly specify
whether to do readaheads for compactions or not.

Test Plan: make check

Reviewers: sheki, heyongqiang, MarkCallaghan

Reviewed By: sheki

CC: leveldb

Differential Revision: https://reviews.facebook.net/D9429
2013-03-20 23:14:03 -07:00

74 lines
2.1 KiB
C++

// Copyright 2008-present Facebook. All Rights Reserved.
#ifndef STORAGE_LEVELDB_INCLUDE_WRITES_ITERATOR_IMPL_H_
#define STORAGE_LEVELDB_INCLUDE_WRITES_ITERATOR_IMPL_H_
#include <vector>
#include "leveldb/env.h"
#include "leveldb/options.h"
#include "leveldb/types.h"
#include "leveldb/transaction_log_iterator.h"
#include "db/log_file.h"
#include "db/log_reader.h"
#include "util/storage_options.h"
namespace leveldb {
struct LogReporter : public log::Reader::Reporter {
Env* env;
Logger* info_log;
uint64_t log_number;
virtual void Corruption(size_t bytes, const Status& s) {
Log(info_log, "%ld: dropping %d bytes; %s",
log_number, static_cast<int>(bytes), s.ToString().c_str());
}
};
class TransactionLogIteratorImpl : public TransactionLogIterator {
public:
TransactionLogIteratorImpl(const std::string& dbname,
const Options* options,
const StorageOptions& soptions,
SequenceNumber& seqNum,
std::vector<LogFile>* files,
SequenceNumber const * const lastFlushedSequence);
virtual ~TransactionLogIteratorImpl() {
// TODO move to cc file.
delete files_;
}
virtual bool Valid();
virtual void Next();
virtual Status status();
virtual BatchResult GetBatch();
private:
const std::string& dbname_;
const Options* options_;
const StorageOptions& soptions_;
const uint64_t sequenceNumber_;
const std::vector<LogFile>* files_;
bool started_;
bool isValid_; // not valid when it starts of.
Status currentStatus_;
size_t currentFileIndex_;
std::unique_ptr<WriteBatch> currentBatch_;
unique_ptr<log::Reader> currentLogReader_;
Status OpenLogFile(const LogFile& logFile, unique_ptr<SequentialFile>* file);
LogReporter NewLogReporter(uint64_t logNumber);
SequenceNumber const * const lastFlushedSequence_;
// represents the sequence number being read currently.
SequenceNumber currentSequence_;
void UpdateCurrentWriteBatch(const Slice& record);
};
} // namespace leveldb
#endif // STORAGE_LEVELDB_INCLUDE_WRITES_ITERATOR_IMPL_H_