rocksdb/util/storage_options.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

64 lines
2.0 KiB
C++

// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
//
#ifndef STORAGE_LEVELDB_UTIL_STORAGE_OPTIONS_H_
#define STORAGE_LEVELDB_UTIL_STORAGE_OPTIONS_H_
#include <string>
#include <stdint.h>
#include "leveldb/env.h"
#include "leveldb/options.h"
namespace leveldb {
// Environment Options that are used to read files from storage
class StorageOptions : public EnvOptions {
public:
/* implicit */ StorageOptions(const Options& opt) :
data_in_os_(opt.allow_os_buffer),
fs_readahead_(opt.allow_readahead),
readahead_compactions_(opt.allow_readahead_compactions),
use_mmap_reads_(opt.allow_mmap_reads),
use_mmap_writes_(opt.allow_mmap_writes) {
}
// copy constructor with readaheads set to readahead_compactions_
StorageOptions(const StorageOptions& opt) {
data_in_os_ = opt.UseOsBuffer();
fs_readahead_ = opt.UseReadaheadCompactions();
readahead_compactions_ = opt.UseReadaheadCompactions();
use_mmap_reads_ = opt.UseMmapReads();
use_mmap_writes_ = opt.UseMmapWrites();
}
// constructor with default options
StorageOptions() {
Options opt;
data_in_os_ = opt.allow_os_buffer;
fs_readahead_ = opt.allow_readahead;
readahead_compactions_ = fs_readahead_;
use_mmap_reads_ = opt.allow_mmap_reads;
use_mmap_writes_ = opt.allow_mmap_writes;
}
virtual ~StorageOptions() {}
bool UseOsBuffer() const { return data_in_os_; };
bool UseReadahead() const { return fs_readahead_; };
bool UseMmapReads() const { return use_mmap_reads_; }
bool UseMmapWrites() const { return use_mmap_writes_; }
bool UseReadaheadCompactions() const { return readahead_compactions_;}
private:
bool data_in_os_;
bool fs_readahead_;
bool readahead_compactions_;
bool use_mmap_reads_;
bool use_mmap_writes_;
};
} // namespace leveldb
#endif // STORAGE_LEVELDB_UTIL_STORAGE_OPTIONS_H_