rocksdb/util/channel.h
Aaron Feldman a69bc91e37 Multithreaded backup and restore in BackupEngineImpl
Summary:
Add a new field: BackupableDBOptions.max_background_copies.
CreateNewBackup() and RestoreDBFromBackup() will use this number of threads to perform copies.
If there is a backup rate limit, then max_background_copies must be 1.
Update backupable_db_test.cc to test multi-threaded backup and restore.
Update backupable_db_test.cc to test backups when the backup environment is not the same as the database environment.

Test Plan:
Run ./backupable_db_test
Run valgrind ./backupable_db_test
Run with TSAN and ASAN

Reviewers: yhchiang, rven, anthony, sdong, igor

Reviewed By: igor

Subscribers: yhchiang, anthony, sdong, leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D40725
2015-07-02 11:35:51 -07:00

68 lines
1.5 KiB
C++

// Copyright (c) 2013, 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.
#include <condition_variable>
#include <mutex>
#include <queue>
#include <utility>
#pragma once
namespace rocksdb {
template <class T>
class channel {
public:
explicit channel() : eof_(false) {}
channel(const channel&) = delete;
void operator=(const channel&) = delete;
void sendEof() {
std::lock_guard<std::mutex> lk(lock_);
eof_ = true;
cv_.notify_all();
}
bool eof() {
std::lock_guard<std::mutex> lk(lock_);
return buffer_.empty() && eof_;
}
size_t size() const {
std::lock_guard<std::mutex> lk(lock_);
return buffer_.size();
}
// writes elem to the queue
void write(T&& elem) {
std::unique_lock<std::mutex> lk(lock_);
buffer_.emplace(std::forward<T>(elem));
cv_.notify_one();
}
/// Moves a dequeued element onto elem, blocking until an element
/// is available.
// returns false if EOF
bool read(T& elem) {
std::unique_lock<std::mutex> lk(lock_);
cv_.wait(lk, [&] { return eof_ || !buffer_.empty(); });
if (eof_ && buffer_.empty()) {
return false;
}
elem = std::move(buffer_.front());
buffer_.pop();
cv_.notify_one();
return true;
}
private:
std::condition_variable cv_;
std::mutex lock_;
std::queue<T> buffer_;
bool eof_;
};
} // namespace rocksdb