#include namespace DB { namespace ErrorCodes { extern const int MEMORY_LIMIT_EXCEEDED; } bool MergeTreeInOrderSelectProcessor::getNewTaskImpl() try { if (all_mark_ranges.empty()) return false; if (!reader) initializeReaders(); MarkRanges mark_ranges_for_task; /// If we need to read few rows, set one range per task to reduce number of read data. if (has_limit_below_one_block) { mark_ranges_for_task = { std::move(all_mark_ranges.front()) }; all_mark_ranges.pop_front(); } else { mark_ranges_for_task = std::move(all_mark_ranges); all_mark_ranges.clear(); } auto size_predictor = (preferred_block_size_bytes == 0) ? nullptr : getSizePredictor(data_part, task_columns, sample_block); task = std::make_unique( data_part, mark_ranges_for_task, part_index_in_query, ordered_names, column_name_set, task_columns.columns, task_columns.pre_columns, prewhere_info && prewhere_info->remove_prewhere_column, task_columns.should_reorder, std::move(size_predictor)); return true; } catch (...) { /// Suspicion of the broken part. A part is added to the queue for verification. if (getCurrentExceptionCode() != ErrorCodes::MEMORY_LIMIT_EXCEEDED) storage.reportBrokenPart(data_part->name); throw; } }