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.
MergeTreeData::DataPartsVector normal_parts;
    for (const auto & part : parts)
    {
        const auto & projections = part->getProjectionParts();
        auto it = projections.find(candidate.desc->name);
        if (it != projections.end())
            projection_parts.push_back(it->second);
        else
            normal_parts.push_back(part);
    }
    if (projection_parts.empty())
        return;
    auto projection_result_ptr = reader.estimateNumMarksToRead(
        projection_parts,
        candidate.required_columns,
        storage_snapshot->metadata,
        candidate.desc->metadata,
        query_info,
        query_context,
        settings.max_threads,
        max_added_blocks);
    if (projection_result_ptr->error())
        return;
    auto sum_marks = projection_result_ptr->marks();
    if (normal_parts.empty())
    {
        /
        /
        candidate.complete = true;
    }