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.
{
    LOG_INFO(log, "Writing CSN {} for mutation {}", csn, mutation_id);
    UInt64 version = MergeTreeMutationEntry::parseFileName(mutation_id);
    std::lock_guard lock(currently_processing_in_background_mutex);
    auto it = current_mutations_by_version.find(version);
    if (it == current_mutations_by_version.end())
        throw Exception(ErrorCodes::LOGICAL_ERROR, "Cannot find mutation {}", mutation_id);
    it->second.writeCSN(csn);
}
void StorageMergeTree::mutate(const MutationCommands & commands, ContextPtr query_context)
{
    
    getPartitionIdsAffectedByCommands(commands, query_context);
    Int64 version = startMutation(commands, query_context);
    if (query_context->getSettingsRef().mutations_sync > 0 || query_context->getCurrentTransaction())
        waitForMutation(version);
}
std::optional<MergeTreeMutationStatus> StorageMergeTree::getIncompleteMutationsStatus(Int64 mutation_version, std::set<String> * mutation_ids) const