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 (force)
    {
        
        auto merge_blocker = stopMergesAndWait();
        auto part = getPartIfExists(part_name, {MergeTreeDataPartState::Active});
        if (!part)
            throw Exception("Part " + part_name + " not found, won't try to drop it.", ErrorCodes::NO_SUCH_DATA_PART);
        removePartsFromWorkingSet(txn, {part}, true);
        return part;
    }
    else
    {
        
        std::unique_lock lock(currently_processing_in_background_mutex);
        auto part = getPartIfExists(part_name, {MergeTreeDataPartState::Active});
        
        if (!part)
            return nullptr;
        
        
        if (currently_merging_mutating_parts.contains(part))
            return nullptr;
        removePartsFromWorkingSet(txn, {part}, true);
        return part;
    }
}
void StorageMergeTree::dropPartNoWaitNoThrow(const String & part_name)