michalursa commented on a change in pull request #12067: URL: https://github.com/apache/arrow/pull/12067#discussion_r826560084
########## File path: cpp/src/arrow/compute/exec/partition_util.h ########## @@ -0,0 +1,95 @@ +// 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. + +#pragma once + +#include <atomic> +#include <cassert> +#include <cstdint> +#include <functional> +#include <random> +#include "arrow/buffer.h" +#include "arrow/compute/exec/util.h" + +namespace arrow { +namespace compute { + +class PartitionSort { + public: + // Bucket sort rows on partition ids. + // Include in the output exclusive cummulative sum of bucket sizes. + // This corresponds to ranges in the sorted array containing all row ids for + // each of the partitions. + // + template <class INPUT_PRTN_ID_FN, class OUTPUT_POS_FN> + static void Eval(int num_rows, int num_prtns, uint16_t* prtn_ranges, + INPUT_PRTN_ID_FN prtn_id_impl, OUTPUT_POS_FN output_pos_impl) { + ARROW_DCHECK(num_rows > 0 && num_rows <= (1 << 15)); + ARROW_DCHECK(num_prtns >= 1 && num_prtns <= (1 << 15)); + + memset(prtn_ranges, 0, (num_prtns + 1) * sizeof(uint16_t)); + + for (int i = 0; i < num_rows; ++i) { + int prtn_id = static_cast<int>(prtn_id_impl(i)); + ++prtn_ranges[prtn_id + 1]; + } + + uint16_t sum = 0; + for (int i = 0; i < num_prtns; ++i) { + uint16_t sum_next = sum + prtn_ranges[i + 1]; + prtn_ranges[i + 1] = sum; + sum = sum_next; + } + + for (int i = 0; i < num_rows; ++i) { + int prtn_id = static_cast<int>(prtn_id_impl(i)); + int pos = prtn_ranges[prtn_id + 1]++; + output_pos_impl(i, pos); + } + } +}; + +class PartitionLocks { + public: + PartitionLocks(); + ~PartitionLocks(); + void Init(int num_prtns); + void CleanUp(); + bool AcquirePartitionLock(int num_prtns, const int* prtns_to_try, bool limit_retries, + int max_retries, int* locked_prtn_id, + int* locked_prtn_id_pos); + void ReleasePartitionLock(int prtn_id); + + private: + std::atomic<bool>* lock_ptr(int prtn_id); + int random_int(int num_values); + + struct PartitionLock { + static constexpr int kCacheLineBytes = 64; + std::atomic<bool> lock; + uint8_t padding[kCacheLineBytes]; + }; + int num_prtns_; + PartitionLock* locks_; Review comment: It can be useful in the future in the spilling scenario if this class will be used across spilled partitions (a different kind of partitions), with changing number of partitions (depending on the sizes of spilled partitions for instance). -- 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]
