westonpace commented on a change in pull request #10955: URL: https://github.com/apache/arrow/pull/10955#discussion_r718114195
########## File path: cpp/src/arrow/dataset/dataset_writer.cc ########## @@ -0,0 +1,529 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +#include "arrow/dataset/dataset_writer.h" + +#include <list> +#include <mutex> +#include <unordered_map> + +#include "arrow/filesystem/path_util.h" +#include "arrow/record_batch.h" +#include "arrow/result.h" +#include "arrow/util/future.h" +#include "arrow/util/logging.h" +#include "arrow/util/map.h" +#include "arrow/util/string.h" + +namespace arrow { +namespace dataset { + +namespace { + +constexpr util::string_view kIntegerToken = "{i}"; + +class Throttle { + public: + explicit Throttle(uint64_t max_value) : max_value_(max_value) {} + + bool Unthrottled() const { return max_value_ <= 0; } + + Future<> Acquire(uint64_t values) { + if (Unthrottled()) { + return Future<>::MakeFinished(); + } + std::lock_guard<std::mutex> lg(mutex_); + if (values + current_value_ > max_value_) { + in_waiting_ = values; + backpressure_ = Future<>::Make(); + } else { + current_value_ += values; + } + return backpressure_; + } + + void Release(uint64_t values) { + if (Unthrottled()) { + return; + } + Future<> to_complete; + { + std::lock_guard<std::mutex> lg(mutex_); + current_value_ -= values; + if (in_waiting_ > 0 && in_waiting_ + current_value_ <= max_value_) { + in_waiting_ = 0; + to_complete = backpressure_; + } + } + if (to_complete.is_valid()) { + to_complete.MarkFinished(); + } + } + + private: + Future<> backpressure_ = Future<>::MakeFinished(); + uint64_t max_value_; + uint64_t in_waiting_ = 0; + uint64_t current_value_ = 0; + std::mutex mutex_; +}; + +class DatasetWriterFileQueue : public util::AsyncDestroyable { + public: + explicit DatasetWriterFileQueue(const Future<std::shared_ptr<FileWriter>>& writer_fut, + const FileSystemDatasetWriteOptions& options, + std::mutex* visitors_mutex) + : options_(options), visitors_mutex_(visitors_mutex) { + running_task_ = Future<>::Make(); + writer_fut.AddCallback( + [this](const Result<std::shared_ptr<FileWriter>>& maybe_writer) { + if (maybe_writer.ok()) { + writer_ = *maybe_writer; + Flush(); + } else { + Abort(maybe_writer.status()); + } + }); + } + + Future<uint64_t> Push(std::shared_ptr<RecordBatch> batch) { + std::unique_lock<std::mutex> lk(mutex); + write_queue_.push_back(std::move(batch)); + Future<uint64_t> write_future = Future<uint64_t>::Make(); + write_futures_.push_back(write_future); + if (!running_task_.is_valid()) { + running_task_ = Future<>::Make(); + FlushUnlocked(std::move(lk)); + } + return write_future; + } + + Future<> DoDestroy() override { + std::lock_guard<std::mutex> lg(mutex); + if (!running_task_.is_valid()) { + RETURN_NOT_OK(DoFinish()); + return Future<>::MakeFinished(); + } + return running_task_.Then([this] { return DoFinish(); }); + } + + private: + Future<uint64_t> WriteNext() { + // May want to prototype / measure someday pushing the async write down further + return DeferNotOk( + io::default_io_context().executor()->Submit([this]() -> Result<uint64_t> { + DCHECK(running_task_.is_valid()); + std::unique_lock<std::mutex> lk(mutex); + const std::shared_ptr<RecordBatch>& to_write = write_queue_.front(); + Future<uint64_t> on_complete = write_futures_.front(); + uint64_t rows_to_write = to_write->num_rows(); + lk.unlock(); + Status status = writer_->Write(to_write); + lk.lock(); + write_queue_.pop_front(); + write_futures_.pop_front(); + lk.unlock(); + if (!status.ok()) { + on_complete.MarkFinished(status); + } else { + on_complete.MarkFinished(rows_to_write); + } + return rows_to_write; + })); + } + + Status DoFinish() { + { + std::lock_guard<std::mutex> lg(*visitors_mutex_); + RETURN_NOT_OK(options_.writer_pre_finish(writer_.get())); + } + RETURN_NOT_OK(writer_->Finish()); + { + std::lock_guard<std::mutex> lg(*visitors_mutex_); + return options_.writer_post_finish(writer_.get()); + } + } + + void Abort(Status err) { + std::vector<Future<uint64_t>> futures_to_abort; + Future<> old_running_task = running_task_; + { + std::lock_guard<std::mutex> lg(mutex); + write_queue_.clear(); + futures_to_abort = + std::vector<Future<uint64_t>>(write_futures_.begin(), write_futures_.end()); + write_futures_.clear(); + running_task_ = Future<>(); + } + for (auto& fut : futures_to_abort) { + fut.MarkFinished(err); + } + old_running_task.MarkFinished(std::move(err)); + } + + void Flush() { + std::unique_lock<std::mutex> lk(mutex); + FlushUnlocked(std::move(lk)); + } + + void FlushUnlocked(std::unique_lock<std::mutex> lk) { + if (write_queue_.empty()) { + Future<> old_running_task = running_task_; + running_task_ = Future<>(); + lk.unlock(); + old_running_task.MarkFinished(); + return; + } + WriteNext().AddCallback([this](const Result<uint64_t>& res) { + if (res.ok()) { + Flush(); + } else { + Abort(res.status()); + } + }); + } + + const FileSystemDatasetWriteOptions& options_; + std::mutex* visitors_mutex_; + std::shared_ptr<FileWriter> writer_; + std::mutex mutex; + std::list<std::shared_ptr<RecordBatch>> write_queue_; + std::list<Future<uint64_t>> write_futures_; + Future<> running_task_; +}; + +struct WriteTask { + std::string filename; + uint64_t num_rows; +}; + +class DatasetWriterDirectoryQueue : public util::AsyncDestroyable { + public: + DatasetWriterDirectoryQueue(std::string directory, std::shared_ptr<Schema> schema, + const FileSystemDatasetWriteOptions& write_options, + Throttle* open_files_throttle, std::mutex* visitors_mutex) + : directory_(std::move(directory)), + schema_(std::move(schema)), + write_options_(write_options), + open_files_throttle_(open_files_throttle), + visitors_mutex_(visitors_mutex) {} + + Result<std::shared_ptr<RecordBatch>> NextWritableChunk( + std::shared_ptr<RecordBatch> batch, std::shared_ptr<RecordBatch>* remainder, + bool* will_open_file) const { + DCHECK_GT(batch->num_rows(), 0); + uint64_t rows_available = std::numeric_limits<uint64_t>::max(); + *will_open_file = rows_written_ == 0; + if (write_options_.max_rows_per_file > 0) { + rows_available = write_options_.max_rows_per_file - rows_written_; + } + + std::shared_ptr<RecordBatch> to_queue; + if (rows_available < static_cast<uint64_t>(batch->num_rows())) { + to_queue = batch->Slice(0, static_cast<int64_t>(rows_available)); + *remainder = batch->Slice(static_cast<int64_t>(rows_available)); + } else { + to_queue = std::move(batch); + } + return to_queue; + } + + Future<WriteTask> StartWrite(const std::shared_ptr<RecordBatch>& batch) { + rows_written_ += batch->num_rows(); + WriteTask task{current_filename_, static_cast<uint64_t>(batch->num_rows())}; + if (!latest_open_file_) { + ARROW_ASSIGN_OR_RAISE(latest_open_file_, OpenFileQueue(current_filename_)); + } + return latest_open_file_->Push(batch).Then([task] { return task; }); + } + + Result<std::string> GetNextFilename() { + auto basename = ::arrow::internal::Replace( + write_options_.basename_template, kIntegerToken, std::to_string(file_counter_++)); + if (!basename) { + return Status::Invalid("string interpolation of basename template failed"); + } + + return fs::internal::ConcatAbstractPath(directory_, *basename); + } + + Status FinishCurrentFile() { + if (latest_open_file_) { + latest_open_file_ = nullptr; + } + rows_written_ = 0; + return GetNextFilename().Value(¤t_filename_); + } + + Result<std::shared_ptr<FileWriter>> OpenWriter(const std::string& filename) { + ARROW_ASSIGN_OR_RAISE(std::shared_ptr<io::OutputStream> out_stream, + write_options_.filesystem->OpenOutputStream(filename)); + return write_options_.format()->MakeWriter(std::move(out_stream), schema_, + write_options_.file_write_options, + {write_options_.filesystem, filename}); + } + + Result<std::shared_ptr<DatasetWriterFileQueue>> OpenFileQueue( + const std::string& filename) { + Future<std::shared_ptr<FileWriter>> file_writer_fut = + init_future_.Then([this, filename] { + ::arrow::internal::Executor* io_executor = + write_options_.filesystem->io_context().executor(); + return DeferNotOk( + io_executor->Submit([this, filename]() { return OpenWriter(filename); })); + }); + auto file_queue = util::MakeSharedAsync<DatasetWriterFileQueue>( + file_writer_fut, write_options_, visitors_mutex_); + RETURN_NOT_OK(task_group_.AddTask( + file_queue->on_closed().Then([this] { open_files_throttle_->Release(1); }))); + return file_queue; + } + + uint64_t rows_written() const { return rows_written_; } + + void PrepareDirectory() { + init_future_ = + DeferNotOk(write_options_.filesystem->io_context().executor()->Submit([this] { + RETURN_NOT_OK(write_options_.filesystem->CreateDir(directory_)); + if (write_options_.existing_data_behavior == kDeleteMatchingPartitions) { + fs::FileSelector selector; + selector.base_dir = directory_; + selector.recursive = true; + return write_options_.filesystem->DeleteFiles(selector); Review comment: Good catch. I switched to using that and removed my changes to `filesystem.h` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
