For some reasons when we delete a MergeTree Part in atomic way something may go wrong - and leave the `delete_tmp_*` folder or it's part on disk. This may lead to a disk space consumption over time.

It's suggested to delete this folders at least at server start-up. Current solution with `clearOldTemporaryDirectories()` doesn't work because this method is called periodically from a thread without any locks or advisory on folders - it may cause the race conditions.
}
        }
    };
    /
    if (minmax_count_projection_candidate)
        prepare_min_max_count_projection();
    /
    if (!selected_candidate || !selected_candidate->complete)
        for (const auto & projection : metadata_snapshot->projections)
            add_projection_candidate(projection);
    /
    if (!candidates.empty())
    {
        query_info.merge_tree_select_result_ptr = reader.estimateNumMarksToRead(
            parts,
            analysis_result.required_columns,
            metadata_snapshot,
            metadata_snapshot,
            query_info,
            query_context,
            settings.max_threads,
            max_added_blocks);
        if (!query_info.merge_tree_select_result_ptr->error())
        {
            /
            /
            auto sum_marks = query_info.merge_tree_select_result_ptr->marks() + 1;
            if (sum_marks < min_sum_marks)
            {
                selected_candidate = nullptr;