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 (!isEmpty())
    {
        WriteBufferFromOwnString buf;
        buf << " Removing parts:";
        for (const auto & part : precommitted_parts)
            buf << " " << part->relative_path;
        buf << ".";
        LOG_DEBUG(data.log, "Undoing transaction.{}", buf.str());
        if (!txn)
        {
            auto lock = data.lockParts();
            for (const auto & part : precommitted_parts)
            {
                DataPartPtr covering_part;
                DataPartsVector covered_parts = data.getActivePartsToReplace(part->info, part->name, covering_part, lock);
                for (auto & covered : covered_parts)
                    covered->version.unlockRemovalTID(Tx::PrehistoricTID, TransactionInfoContext{data.getStorageID(), covered->name});
            }
        }
        data.removePartsFromWorkingSet(txn,
            DataPartsVector(precommitted_parts.begin(), precommitted_parts.end()),
            / true);
    }
    clear();
}
MergeTreeData::DataPartsVector MergeTreeData::Transaction::commit(MergeTreeData::DataPartsLock * acquired_parts_lock)