rocksdb/util/delete_scheduler.cc

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// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#ifndef ROCKSDB_LITE
#include "util/delete_scheduler.h"
#include <thread>
#include <vector>
#include "port/port.h"
#include "rocksdb/env.h"
#include "util/logging.h"
#include "util/mutexlock.h"
#include "util/sst_file_manager_impl.h"
#include "util/sync_point.h"
namespace rocksdb {
DeleteScheduler::DeleteScheduler(Env* env, const std::string& trash_dir,
int64_t rate_bytes_per_sec, Logger* info_log,
SstFileManagerImpl* sst_file_manager)
: env_(env),
trash_dir_(trash_dir),
total_trash_size_(0),
rate_bytes_per_sec_(rate_bytes_per_sec),
pending_files_(0),
closing_(false),
cv_(&mu_),
info_log_(info_log),
sst_file_manager_(sst_file_manager) {
assert(sst_file_manager != nullptr);
bg_thread_.reset(
new port::Thread(&DeleteScheduler::BackgroundEmptyTrash, this));
}
DeleteScheduler::~DeleteScheduler() {
{
InstrumentedMutexLock l(&mu_);
closing_ = true;
cv_.SignalAll();
}
if (bg_thread_) {
bg_thread_->join();
}
}
Status DeleteScheduler::DeleteFile(const std::string& file_path) {
Status s;
if (rate_bytes_per_sec_.load() <= 0 ||
total_trash_size_.load() >
sst_file_manager_->GetTotalSize() * max_trash_db_ratio_) {
// Rate limiting is disabled or trash size makes up more than
// max_trash_db_ratio_ (default 25%) of the total DB size
TEST_SYNC_POINT("DeleteScheduler::DeleteFile");
s = env_->DeleteFile(file_path);
if (s.ok()) {
sst_file_manager_->OnDeleteFile(file_path);
}
return s;
}
// Move file to trash
std::string path_in_trash;
s = MoveToTrash(file_path, &path_in_trash);
if (!s.ok()) {
ROCKS_LOG_ERROR(info_log_, "Failed to move %s to trash directory (%s)",
file_path.c_str(), trash_dir_.c_str());
s = env_->DeleteFile(file_path);
if (s.ok()) {
sst_file_manager_->OnDeleteFile(file_path);
}
return s;
}
// Add file to delete queue
{
InstrumentedMutexLock l(&mu_);
queue_.push(path_in_trash);
pending_files_++;
if (pending_files_ == 1) {
cv_.SignalAll();
}
}
return s;
}
std::map<std::string, Status> DeleteScheduler::GetBackgroundErrors() {
InstrumentedMutexLock l(&mu_);
return bg_errors_;
}
Status DeleteScheduler::MoveToTrash(const std::string& file_path,
std::string* path_in_trash) {
Status s;
// Figure out the name of the file in trash folder
size_t idx = file_path.rfind("/");
if (idx == std::string::npos || idx == file_path.size() - 1) {
return Status::InvalidArgument("file_path is corrupted");
}
*path_in_trash = trash_dir_ + file_path.substr(idx);
std::string unique_suffix = "";
if (*path_in_trash == file_path) {
// This file is already in trash
return s;
}
// TODO(tec) : Implement Env::RenameFileIfNotExist and remove
// file_move_mu mutex.
InstrumentedMutexLock l(&file_move_mu_);
while (true) {
s = env_->FileExists(*path_in_trash + unique_suffix);
if (s.IsNotFound()) {
// We found a path for our file in trash
*path_in_trash += unique_suffix;
s = env_->RenameFile(file_path, *path_in_trash);
break;
} else if (s.ok()) {
// Name conflict, generate new random suffix
unique_suffix = env_->GenerateUniqueId();
} else {
// Error during FileExists call, we cannot continue
break;
}
}
if (s.ok()) {
uint64_t trash_file_size = 0;
sst_file_manager_->OnMoveFile(file_path, *path_in_trash, &trash_file_size);
total_trash_size_.fetch_add(trash_file_size);
}
return s;
}
void DeleteScheduler::BackgroundEmptyTrash() {
TEST_SYNC_POINT("DeleteScheduler::BackgroundEmptyTrash");
while (true) {
InstrumentedMutexLock l(&mu_);
while (queue_.empty() && !closing_) {
cv_.Wait();
}
if (closing_) {
return;
}
// Delete all files in queue_
uint64_t start_time = env_->NowMicros();
uint64_t total_deleted_bytes = 0;
int64_t current_delete_rate = rate_bytes_per_sec_.load();
while (!queue_.empty() && !closing_) {
if (current_delete_rate != rate_bytes_per_sec_.load()) {
// User changed the delete rate
current_delete_rate = rate_bytes_per_sec_.load();
start_time = env_->NowMicros();
total_deleted_bytes = 0;
}
// Get new file to delete
std::string path_in_trash = queue_.front();
queue_.pop();
// We dont need to hold the lock while deleting the file
mu_.Unlock();
uint64_t deleted_bytes = 0;
// Delete file from trash and update total_penlty value
Status s = DeleteTrashFile(path_in_trash, &deleted_bytes);
total_deleted_bytes += deleted_bytes;
mu_.Lock();
if (!s.ok()) {
bg_errors_[path_in_trash] = s;
}
// Apply penlty if necessary
uint64_t total_penlty;
if (current_delete_rate > 0) {
// rate limiting is enabled
total_penlty =
((total_deleted_bytes * kMicrosInSecond) / current_delete_rate);
while (!closing_ && !cv_.TimedWait(start_time + total_penlty)) {}
} else {
// rate limiting is disabled
total_penlty = 0;
}
TEST_SYNC_POINT_CALLBACK("DeleteScheduler::BackgroundEmptyTrash:Wait",
&total_penlty);
pending_files_--;
if (pending_files_ == 0) {
// Unblock WaitForEmptyTrash since there are no more files waiting
// to be deleted
cv_.SignalAll();
}
}
}
}
Status DeleteScheduler::DeleteTrashFile(const std::string& path_in_trash,
uint64_t* deleted_bytes) {
uint64_t file_size;
Status s = env_->GetFileSize(path_in_trash, &file_size);
if (s.ok()) {
TEST_SYNC_POINT("DeleteScheduler::DeleteTrashFile:DeleteFile");
s = env_->DeleteFile(path_in_trash);
}
if (!s.ok()) {
// Error while getting file size or while deleting
ROCKS_LOG_ERROR(info_log_, "Failed to delete %s from trash -- %s",
path_in_trash.c_str(), s.ToString().c_str());
*deleted_bytes = 0;
} else {
*deleted_bytes = file_size;
total_trash_size_.fetch_sub(file_size);
sst_file_manager_->OnDeleteFile(path_in_trash);
}
return s;
}
void DeleteScheduler::WaitForEmptyTrash() {
InstrumentedMutexLock l(&mu_);
while (pending_files_ > 0 && !closing_) {
cv_.Wait();
}
}
} // namespace rocksdb
#endif // ROCKSDB_LITE