github-actions[bot] commented on code in PR #28103: URL: https://github.com/apache/doris/pull/28103#discussion_r1432482896
########## be/src/olap/parallel_scanner_builder.cpp: ########## @@ -0,0 +1,474 @@ +// 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 "parallel_scanner_builder.h" + +#include "exec/olap_utils.h" +#include "olap/iterators.h" +#include "olap/primary_key_index.h" +#include "olap/row_cursor.h" +#include "olap/rowset/beta_rowset.h" +#include "olap/rowset/segment_v2/segment.h" +#include "olap/short_key_index.h" +#include "util/key_util.h" +#include "vec/exec/scan/new_olap_scanner.h" + +namespace doris { + +using namespace vectorized; + +using SplitKey = StorageReadOptions::SplitKey; +using SplitKeyRange = StorageReadOptions::SplitKeyRange; + +template <typename ParentType> +Status ParallelScannerBuilder<ParentType>::build_scanners(std::list<VScannerSPtr>& scanners) { + RETURN_IF_ERROR(_load()); + if (_is_dup_mow_key) { + return _build_scanners_by_rowid(scanners); + } else { + return _build_scanners_by_key_range(scanners); + } +} + +template <typename ParentType> +Status ParallelScannerBuilder<ParentType>::_build_scanners_by_rowid( + std::list<VScannerSPtr>& scanners) { + DCHECK_GE(_rows_per_scanner, _min_rows_per_scanner); + for (auto&& [tablet, version] : _tablets) { + DCHECK(_all_rowsets.contains(tablet->tablet_id())); + auto& rowsets = _all_rowsets[tablet->tablet_id()]; + + TabletReader::ReadSource reade_source_with_delete_info; + if (!_state->skip_delete_predicate()) { + RETURN_IF_ERROR(tablet->capture_rs_readers( + {0, version}, &reade_source_with_delete_info.rs_splits, false)); + reade_source_with_delete_info.fill_delete_predicates(); + } + + TabletReader::ReadSource read_source; + + int64_t rows_collected = 0; + for (auto& rowset : rowsets) { + auto beta_rowset = std::dynamic_pointer_cast<BetaRowset>(rowset); + RowsetReaderSharedPtr reader; + RETURN_IF_ERROR(beta_rowset->create_reader(&reader)); + const auto rowset_id = beta_rowset->rowset_id(); + + DCHECK(_segment_cache_handles.contains(rowset_id)); + auto& segment_cache_handle = _segment_cache_handles[rowset_id]; + + if (beta_rowset->num_rows() == 0) { + continue; + } + + const auto& segments = segment_cache_handle.get_segments(); + int segment_start = 0; + auto split = RowSetSplits(reader->clone()); + + for (size_t i = 0; i != segments.size(); ++i) { + const auto& segment = segments[i]; + RowRanges row_ranges; + const size_t rows_of_segment = segment->num_rows(); + int64_t offset_in_segment = 0; + + // try to split large segments into RowRanges + while (offset_in_segment < rows_of_segment) { + const int64_t remaining_rows = rows_of_segment - offset_in_segment; + auto rows_need = _rows_per_scanner - rows_collected; + + // 0.9: try to avoid splitting the segments into excessively small parts. + if (rows_need >= remaining_rows * 0.9) { + rows_need = remaining_rows; + } + DCHECK_LE(rows_need, remaining_rows); + + // RowRange stands for range: [From, To), From is inclusive, To is exclusive. + row_ranges.add({offset_in_segment, + offset_in_segment + static_cast<int64_t>(rows_need)}); + rows_collected += rows_need; + offset_in_segment += rows_need; + + // If collected enough rows, build a new scanner + if (rows_collected >= _rows_per_scanner) { + split.segment_offsets.first = segment_start, + split.segment_offsets.second = i + 1; + split.segment_row_ranges.emplace_back(std::move(row_ranges)); + + DCHECK_EQ(split.segment_offsets.second - split.segment_offsets.first, + split.segment_row_ranges.size()); + + read_source.rs_splits.emplace_back(std::move(split)); + + scanners.emplace_back( + _build_scanner(tablet, version, _key_ranges, + {std::move(read_source.rs_splits), + reade_source_with_delete_info.delete_predicates})); + + read_source = TabletReader::ReadSource(); + split = RowSetSplits(reader->clone()); + row_ranges = RowRanges(); + + segment_start = offset_in_segment < rows_of_segment ? i : i + 1; + rows_collected = 0; + } + } + + // The non-empty `row_ranges` means there are some rows left in this segment not added into `split`. + if (!row_ranges.is_empty()) { + DCHECK_GT(rows_collected, 0); + DCHECK_EQ(row_ranges.to(), segment->num_rows()); + split.segment_row_ranges.emplace_back(std::move(row_ranges)); + } + } + + DCHECK_LE(rows_collected, _rows_per_scanner); + if (rows_collected > 0) { + split.segment_offsets.first = segment_start; + split.segment_offsets.second = segments.size(); + DCHECK_GT(split.segment_offsets.second, split.segment_offsets.first); + DCHECK_EQ(split.segment_row_ranges.size(), + split.segment_offsets.second - split.segment_offsets.first); + read_source.rs_splits.emplace_back(std::move(split)); + } + } // end `for (auto& rowset : rowsets)` + + DCHECK_LE(rows_collected, _rows_per_scanner); + if (rows_collected > 0) { + DCHECK_GT(read_source.rs_splits.size(), 0); +#ifndef NDEBUG + for (auto& split : read_source.rs_splits) { + DCHECK(split.rs_reader != nullptr); + DCHECK_LT(split.segment_offsets.first, split.segment_offsets.second); + DCHECK_EQ(split.segment_row_ranges.size(), + split.segment_offsets.second - split.segment_offsets.first); + } +#endif + scanners.emplace_back( + _build_scanner(tablet, version, _key_ranges, + {std::move(read_source.rs_splits), + reade_source_with_delete_info.delete_predicates})); + } + } + + return Status::OK(); +} + +/** + * Load rowsets of each tablet with specified version, segments of each rowset. + */ +template <typename ParentType> +Status ParallelScannerBuilder<ParentType>::_load() { + for (auto&& [tablet, version] : _tablets) { + const auto tablet_id = tablet->tablet_id(); + _tablets_rows.emplace_back(0); + auto& rows = _tablets_rows.back(); + auto& rowsets = _all_rowsets[tablet_id]; + RETURN_IF_ERROR(tablet->capture_consistent_rowsets({0, version}, &rowsets)); + + for (auto& rowset : rowsets) { + RETURN_IF_ERROR(rowset->load()); + const auto rowset_id = rowset->rowset_id(); + auto& segment_cache_handle = _segment_cache_handles[rowset_id]; + + /// All loaded segments will be cached into segment_cache_handle. + RETURN_IF_ERROR(SegmentLoader::instance()->load_segments( + std::dynamic_pointer_cast<BetaRowset>(rowset), &segment_cache_handle, true)); + _total_rows += rowset->num_rows(); + rows += _total_rows; + } + } + + _rows_per_scanner = _total_rows / _max_scanners_count; + _rows_per_scanner = std::max<size_t>(_rows_per_scanner, _min_rows_per_scanner); + + return Status::OK(); +} + +template <typename ParentType> +std::unique_ptr<SegmentGroup> +ParallelScannerBuilder<ParentType>::_create_segment_group_from_rowsets( + const std::vector<RowsetSharedPtr>& rowsets) { + if (rowsets.empty()) { + return {}; + } + + size_t max_rows = 0; + auto segment_group = std::make_unique<SegmentGroup>(); + for (const auto& rowset : rowsets) { + const auto rowset_id = rowset->rowset_id(); + DCHECK(_segment_cache_handles.contains(rowset_id)); + auto& cache_handle = _segment_cache_handles[rowset_id]; + auto& segments = cache_handle.get_segments(); + + if (segments.empty()) { + continue; + } + + if (rowset->is_segments_overlapping()) { + auto* largest_segment = segments[0].get(); + for (size_t i = 1; i != segments.size(); ++i) { + if (segments[i]->num_rows() > largest_segment->num_rows()) { + largest_segment = segments[i].get(); + } + } + + if (largest_segment->num_rows() > max_rows) { + segment_group->rowset = rowset; + segment_group->num_rows = largest_segment->num_rows(); + segment_group->segments.clear(); + segment_group->segments.emplace_back(largest_segment); + max_rows = largest_segment->num_rows(); + } + } else if (rowset->num_rows() > max_rows) { + max_rows = rowset->num_rows(); + segment_group->rowset = rowset; + segment_group->segments.clear(); + segment_group->segments.reserve(segments.size()); + segment_group->num_rows = 0; + for (auto& segment : segments) { + segment_group->num_rows += segment->num_rows(); + segment_group->segments.emplace_back(segment.get()); + } + } + } + + if (max_rows == 0) { + return {}; + } + + DCHECK(segment_group->rowset != nullptr); + return segment_group; +} + +template <typename ParentType> +Status ParallelScannerBuilder<ParentType>::_parse_segment_group(SegmentGroup& group) { + for (auto* segment : group.segments) { + RETURN_IF_ERROR(segment->load_index()); + const ShortKeyIndexDecoder* index = segment->get_short_key_index(); + group.num_blocks += index->num_items(); + } + return Status::OK(); +} + +template <typename ParentType> +std::shared_ptr<NewOlapScanner> ParallelScannerBuilder<ParentType>::_build_scanner( + BaseTabletSPtr tablet, int64_t version, const std::vector<OlapScanRange*>& key_ranges, + TabletReader::ReadSource&& read_source) { + NewOlapScanner::Params params { + _state, _scanner_profile.get(), key_ranges, std::move(tablet), + version, std::move(read_source), _limit_per_scanner, _is_preaggregation}; + return NewOlapScanner::create_shared(_parent, std::move(params)); +} + +// Convert key ranges from `OlapScanRange` to `RowCursor` and then encode them into `std::string`. +template <typename ParentType> +Status ParallelScannerBuilder<ParentType>::_convert_key_ranges( + const TabletSPtr& tablet, std::vector<std::string>& start_keys, + std::vector<std::string>& end_keys, std::vector<bool>& include_begin_keys, + std::vector<bool>& include_end_keys, std::shared_ptr<Schema>& schema) { + DCHECK(start_keys.empty()); + DCHECK(end_keys.empty()); + + TabletSchemaSPtr tablet_schema = tablet->tablet_schema(); + + std::vector<uint32_t> columns; + if (_key_ranges.empty()) { + columns.resize(tablet->num_short_key_columns()); + } else { + DCHECK_EQ(_key_ranges.front()->end_scan_range.size(), + _key_ranges.front()->begin_scan_range.size()); + columns.resize(_key_ranges.front()->end_scan_range.size()); + } + + std::iota(columns.begin(), columns.end(), 0); + schema = std::make_shared<Schema>(tablet_schema->columns(), columns); + + if (_key_ranges.empty()) { + /// Empty `std::string` means the min/max value of keys which will be handled in `SegmentIterator`. + start_keys.emplace_back(); + end_keys.emplace_back(); + include_begin_keys.emplace_back(true); + include_end_keys.emplace_back(true); + return Status::OK(); + } + + for (auto& key_range : _key_ranges) { + start_keys.emplace_back(); + end_keys.emplace_back(); + + include_begin_keys.emplace_back(key_range->begin_include); + include_end_keys.emplace_back(key_range->end_include); + + RowCursor start_key; + RowCursor end_key; + RETURN_IF_ERROR(start_key.init_scan_key(tablet->tablet_schema(), + key_range->begin_scan_range.values(), schema)); + RETURN_IF_ERROR(start_key.from_tuple(key_range->begin_scan_range)); + + encode_key_with_padding(&start_keys.back(), start_key, + tablet_schema->num_short_key_columns(), key_range->begin_include); + + RETURN_IF_ERROR(end_key.init_scan_key(tablet->tablet_schema(), + key_range->end_scan_range.values(), schema)); + RETURN_IF_ERROR(end_key.from_tuple(key_range->end_scan_range)); + + encode_key_with_padding(&end_keys.back(), end_key, tablet_schema->num_short_key_columns(), + !key_range->end_include); + } + + return Status::OK(); +} + +template <typename ParentType> +Status ParallelScannerBuilder<ParentType>::_build_scanners_by_key_range( Review Comment: warning: function '_build_scanners_by_key_range' exceeds recommended size/complexity thresholds [readability-function-size] ```cpp Status ParallelScannerBuilder<ParentType>::_build_scanners_by_key_range( ^ ``` <details> <summary>Additional context</summary> **be/src/olap/parallel_scanner_builder.cpp:336:** 132 lines including whitespace and comments (threshold 80) ```cpp Status ParallelScannerBuilder<ParentType>::_build_scanners_by_key_range( ^ ``` </details> -- This is an automated message from the Apache Git Service. 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