ce52274640
Summary: Using const string& can avoid one extra string copy. This PR addresses a recent comment made by siying on #3933. Pull Request resolved: https://github.com/facebook/rocksdb/pull/4491 Differential Revision: D10381211 Pulled By: riversand963 fbshipit-source-id: 27fc2d65d84bc7cd07833c77cdc47f06dcfaeb31
328 lines
11 KiB
C++
328 lines
11 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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//
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// 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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#pragma once
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#include <atomic>
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#include <sstream>
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#include <string>
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#include "port/port.h"
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#include "rocksdb/env.h"
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#include "rocksdb/listener.h"
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#include "rocksdb/rate_limiter.h"
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#include "util/aligned_buffer.h"
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#include "util/sync_point.h"
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namespace rocksdb {
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class Statistics;
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class HistogramImpl;
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std::unique_ptr<RandomAccessFile> NewReadaheadRandomAccessFile(
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std::unique_ptr<RandomAccessFile>&& file, size_t readahead_size);
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class SequentialFileReader {
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private:
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std::unique_ptr<SequentialFile> file_;
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std::string file_name_;
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std::atomic<size_t> offset_; // read offset
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public:
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explicit SequentialFileReader(std::unique_ptr<SequentialFile>&& _file,
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const std::string& _file_name)
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: file_(std::move(_file)), file_name_(_file_name), offset_(0) {}
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SequentialFileReader(SequentialFileReader&& o) ROCKSDB_NOEXCEPT {
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*this = std::move(o);
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}
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SequentialFileReader& operator=(SequentialFileReader&& o) ROCKSDB_NOEXCEPT {
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file_ = std::move(o.file_);
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return *this;
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}
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SequentialFileReader(const SequentialFileReader&) = delete;
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SequentialFileReader& operator=(const SequentialFileReader&) = delete;
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Status Read(size_t n, Slice* result, char* scratch);
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Status Skip(uint64_t n);
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void Rewind();
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SequentialFile* file() { return file_.get(); }
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std::string file_name() { return file_name_; }
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bool use_direct_io() const { return file_->use_direct_io(); }
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};
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class RandomAccessFileReader {
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private:
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#ifndef ROCKSDB_LITE
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void NotifyOnFileReadFinish(uint64_t offset, size_t length, time_t start_ts,
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const Status& status) const {
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FileOperationInfo info(file_name_);
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info.offset = offset;
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info.length = length;
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info.start_timestamp = start_ts;
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time_t finish_ts =
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std::chrono::system_clock::to_time_t(std::chrono::system_clock::now());
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info.finish_timestamp = finish_ts;
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info.status = status;
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for (auto& listener : listeners_) {
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listener->OnFileReadFinish(info);
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}
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}
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#endif // ROCKSDB_LITE
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bool ShouldNotifyListeners() const { return !listeners_.empty(); }
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std::unique_ptr<RandomAccessFile> file_;
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std::string file_name_;
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Env* env_;
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Statistics* stats_;
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uint32_t hist_type_;
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HistogramImpl* file_read_hist_;
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RateLimiter* rate_limiter_;
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bool for_compaction_;
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std::vector<std::shared_ptr<EventListener>> listeners_;
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public:
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explicit RandomAccessFileReader(
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std::unique_ptr<RandomAccessFile>&& raf, std::string _file_name,
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Env* env = nullptr, Statistics* stats = nullptr, uint32_t hist_type = 0,
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HistogramImpl* file_read_hist = nullptr,
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RateLimiter* rate_limiter = nullptr, bool for_compaction = false,
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const std::vector<std::shared_ptr<EventListener>>& listeners = {})
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: file_(std::move(raf)),
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file_name_(std::move(_file_name)),
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env_(env),
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stats_(stats),
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hist_type_(hist_type),
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file_read_hist_(file_read_hist),
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rate_limiter_(rate_limiter),
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for_compaction_(for_compaction),
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listeners_() {
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#ifndef ROCKSDB_LITE
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std::for_each(listeners.begin(), listeners.end(),
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[this](const std::shared_ptr<EventListener>& e) {
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if (e->ShouldBeNotifiedOnFileIO()) {
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listeners_.emplace_back(e);
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}
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});
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#else // !ROCKSDB_LITE
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(void)listeners;
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#endif
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}
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RandomAccessFileReader(RandomAccessFileReader&& o) ROCKSDB_NOEXCEPT {
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*this = std::move(o);
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}
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RandomAccessFileReader& operator=(RandomAccessFileReader&& o)
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ROCKSDB_NOEXCEPT {
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file_ = std::move(o.file_);
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env_ = std::move(o.env_);
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stats_ = std::move(o.stats_);
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hist_type_ = std::move(o.hist_type_);
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file_read_hist_ = std::move(o.file_read_hist_);
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rate_limiter_ = std::move(o.rate_limiter_);
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for_compaction_ = std::move(o.for_compaction_);
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return *this;
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}
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RandomAccessFileReader(const RandomAccessFileReader&) = delete;
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RandomAccessFileReader& operator=(const RandomAccessFileReader&) = delete;
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Status Read(uint64_t offset, size_t n, Slice* result, char* scratch) const;
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Status Prefetch(uint64_t offset, size_t n) const {
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return file_->Prefetch(offset, n);
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}
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RandomAccessFile* file() { return file_.get(); }
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std::string file_name() const { return file_name_; }
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bool use_direct_io() const { return file_->use_direct_io(); }
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};
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// Use posix write to write data to a file.
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class WritableFileWriter {
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private:
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#ifndef ROCKSDB_LITE
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void NotifyOnFileWriteFinish(uint64_t offset, size_t length, time_t start_ts,
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const Status& status) {
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FileOperationInfo info(file_name_);
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info.offset = offset;
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info.length = length;
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info.start_timestamp = start_ts;
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time_t finish_ts =
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std::chrono::system_clock::to_time_t(std::chrono::system_clock::now());
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info.finish_timestamp = finish_ts;
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info.status = status;
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for (auto& listener : listeners_) {
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listener->OnFileWriteFinish(info);
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}
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}
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#endif // ROCKSDB_LITE
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bool ShouldNotifyListeners() const { return !listeners_.empty(); }
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std::unique_ptr<WritableFile> writable_file_;
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std::string file_name_;
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AlignedBuffer buf_;
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size_t max_buffer_size_;
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// Actually written data size can be used for truncate
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// not counting padding data
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uint64_t filesize_;
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#ifndef ROCKSDB_LITE
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// This is necessary when we use unbuffered access
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// and writes must happen on aligned offsets
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// so we need to go back and write that page again
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uint64_t next_write_offset_;
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#endif // ROCKSDB_LITE
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bool pending_sync_;
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uint64_t last_sync_size_;
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uint64_t bytes_per_sync_;
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RateLimiter* rate_limiter_;
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Statistics* stats_;
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std::vector<std::shared_ptr<EventListener>> listeners_;
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public:
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WritableFileWriter(
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std::unique_ptr<WritableFile>&& file, const std::string& _file_name,
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const EnvOptions& options, Statistics* stats = nullptr,
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const std::vector<std::shared_ptr<EventListener>>& listeners = {})
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: writable_file_(std::move(file)),
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file_name_(_file_name),
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buf_(),
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max_buffer_size_(options.writable_file_max_buffer_size),
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filesize_(0),
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#ifndef ROCKSDB_LITE
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next_write_offset_(0),
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#endif // ROCKSDB_LITE
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pending_sync_(false),
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last_sync_size_(0),
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bytes_per_sync_(options.bytes_per_sync),
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rate_limiter_(options.rate_limiter),
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stats_(stats),
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listeners_() {
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TEST_SYNC_POINT_CALLBACK("WritableFileWriter::WritableFileWriter:0",
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reinterpret_cast<void*>(max_buffer_size_));
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buf_.Alignment(writable_file_->GetRequiredBufferAlignment());
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buf_.AllocateNewBuffer(std::min((size_t)65536, max_buffer_size_));
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#ifndef ROCKSDB_LITE
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std::for_each(listeners.begin(), listeners.end(),
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[this](const std::shared_ptr<EventListener>& e) {
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if (e->ShouldBeNotifiedOnFileIO()) {
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listeners_.emplace_back(e);
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}
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});
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#else // !ROCKSDB_LITE
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(void)listeners;
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#endif
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}
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WritableFileWriter(const WritableFileWriter&) = delete;
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WritableFileWriter& operator=(const WritableFileWriter&) = delete;
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~WritableFileWriter() { Close(); }
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std::string file_name() const { return file_name_; }
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Status Append(const Slice& data);
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Status Pad(const size_t pad_bytes);
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Status Flush();
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Status Close();
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Status Sync(bool use_fsync);
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// Sync only the data that was already Flush()ed. Safe to call concurrently
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// with Append() and Flush(). If !writable_file_->IsSyncThreadSafe(),
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// returns NotSupported status.
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Status SyncWithoutFlush(bool use_fsync);
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uint64_t GetFileSize() { return filesize_; }
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Status InvalidateCache(size_t offset, size_t length) {
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return writable_file_->InvalidateCache(offset, length);
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}
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WritableFile* writable_file() const { return writable_file_.get(); }
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bool use_direct_io() { return writable_file_->use_direct_io(); }
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bool TEST_BufferIsEmpty() { return buf_.CurrentSize() == 0; }
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private:
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// Used when os buffering is OFF and we are writing
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// DMA such as in Direct I/O mode
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#ifndef ROCKSDB_LITE
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Status WriteDirect();
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#endif // !ROCKSDB_LITE
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// Normal write
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Status WriteBuffered(const char* data, size_t size);
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Status RangeSync(uint64_t offset, uint64_t nbytes);
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Status SyncInternal(bool use_fsync);
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};
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// FilePrefetchBuffer can automatically do the readahead if file_reader,
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// readahead_size, and max_readahead_size are passed in.
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// max_readahead_size should be greater than or equal to readahead_size.
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// readahead_size will be doubled on every IO, until max_readahead_size.
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class FilePrefetchBuffer {
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public:
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// If `track_min_offset` is true, track minimum offset ever read.
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FilePrefetchBuffer(RandomAccessFileReader* file_reader = nullptr,
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size_t readadhead_size = 0, size_t max_readahead_size = 0,
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bool enable = true, bool track_min_offset = false)
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: buffer_offset_(0),
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file_reader_(file_reader),
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readahead_size_(readadhead_size),
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max_readahead_size_(max_readahead_size),
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min_offset_read_(port::kMaxSizet),
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enable_(enable),
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track_min_offset_(track_min_offset) {}
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Status Prefetch(RandomAccessFileReader* reader, uint64_t offset, size_t n);
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bool TryReadFromCache(uint64_t offset, size_t n, Slice* result);
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// The minimum `offset` ever passed to TryReadFromCache(). Only be tracked
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// if track_min_offset = true.
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size_t min_offset_read() const { return min_offset_read_; }
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private:
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AlignedBuffer buffer_;
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uint64_t buffer_offset_;
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RandomAccessFileReader* file_reader_;
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size_t readahead_size_;
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size_t max_readahead_size_;
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// The minimum `offset` ever passed to TryReadFromCache().
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size_t min_offset_read_;
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// if false, TryReadFromCache() always return false, and we only take stats
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// for track_min_offset_ if track_min_offset_ = true
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bool enable_;
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// If true, track minimum `offset` ever passed to TryReadFromCache(), which
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// can be fetched from min_offset_read().
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bool track_min_offset_;
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};
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extern Status NewWritableFile(Env* env, const std::string& fname,
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unique_ptr<WritableFile>* result,
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const EnvOptions& options);
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bool ReadOneLine(std::istringstream* iss, SequentialFile* seq_file,
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std::string* output, bool* has_data, Status* result);
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} // namespace rocksdb
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