rocksdb/include/rocksdb/sst_file_writer.h
Islam AbdelRahman d58ef52ba6 Allow SstFileWriter to Fadvise the file away from page cache
Summary:
Add `fadvise_trigger` option to `SstFileWriter`

If fadvise_trigger is passed with a non-zero value, SstFileWriter will invalidate the os page cache every `fadvise_trigger` bytes for the sst file
Closes https://github.com/facebook/rocksdb/pull/1731

Differential Revision: D4371246

Pulled By: IslamAbdelRahman

fbshipit-source-id: 91caff1
2016-12-29 15:09:19 -08:00

82 lines
3.1 KiB
C++

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
#pragma once
#include <string>
#include "rocksdb/env.h"
#include "rocksdb/options.h"
#include "rocksdb/table_properties.h"
#include "rocksdb/types.h"
namespace rocksdb {
class Comparator;
// ExternalSstFileInfo include information about sst files created
// using SstFileWriter
struct ExternalSstFileInfo {
ExternalSstFileInfo() {}
ExternalSstFileInfo(const std::string& _file_path,
const std::string& _smallest_key,
const std::string& _largest_key,
SequenceNumber _sequence_number, uint64_t _file_size,
int32_t _num_entries, int32_t _version)
: file_path(_file_path),
smallest_key(_smallest_key),
largest_key(_largest_key),
sequence_number(_sequence_number),
file_size(_file_size),
num_entries(_num_entries),
version(_version) {}
std::string file_path; // external sst file path
std::string smallest_key; // smallest user key in file
std::string largest_key; // largest user key in file
SequenceNumber sequence_number; // sequence number of all keys in file
uint64_t file_size; // file size in bytes
uint64_t num_entries; // number of entries in file
int32_t version; // file version
};
// SstFileWriter is used to create sst files that can be added to database later
// All keys in files generated by SstFileWriter will have sequence number = 0
class SstFileWriter {
public:
// User can pass `column_family` to specify that the the generated file will
// be ingested into this column_family, note that passing nullptr means that
// the column_family is unknown.
// If invalidate_page_cache is set to true, SstFileWriter will give the OS a
// hint that this file pages is not needed everytime we write 1MB to the file
SstFileWriter(const EnvOptions& env_options, const Options& options,
const Comparator* user_comparator,
ColumnFamilyHandle* column_family = nullptr,
bool invalidate_page_cache = true);
~SstFileWriter();
// Prepare SstFileWriter to write into file located at "file_path".
Status Open(const std::string& file_path);
// Add key, value to currently opened file
// REQUIRES: key is after any previously added key according to comparator.
Status Add(const Slice& user_key, const Slice& value);
// Finalize writing to sst file and close file.
//
// An optional ExternalSstFileInfo pointer can be passed to the function
// which will be populated with information about the created sst file
Status Finish(ExternalSstFileInfo* file_info = nullptr);
// Return the current file size.
uint64_t FileSize();
private:
void InvalidatePageCache(bool closing);
struct Rep;
Rep* rep_;
};
} // namespace rocksdb