And waits for them. That's pointless.
new_data_part->index_granularity_info = source_part->index_granularity_info;
    new_data_part->setColumns(getColumnsForNewDataPart(source_part, updated_header, storage_columns, for_file_renames));
    new_data_part->partition.assign(source_part->partition);
    auto disk = new_data_part->volume->getDisk();
    String new_part_tmp_path = new_data_part->getFullRelativePath();
    SyncGuardPtr sync_guard;
    if (data.getSettings()->fsync_part_directory)
        sync_guard = disk->getDirectorySyncGuard(new_part_tmp_path);
    
    auto mrk_extension = source_part->index_granularity_info.is_adaptive ? getAdaptiveMrkExtension(new_data_part->getType())
                                                                         : getNonAdaptiveMrkExtension();
    bool need_sync = needSyncPart(source_part->rows_count, source_part->getBytesOnDisk(), *data_settings);
    bool need_remove_expired_values = false;
    if (in && shouldExecuteTTL(metadata_snapshot, in->getHeader().getNamesAndTypesList().getNames(), commands_for_part))
        need_remove_expired_values = true;
    
    
    if (!isWidePart(source_part)
        || (mutation_kind == MutationsInterpreter::MutationKind::MUTATE_OTHER && interpreter && interpreter->isAffectingAllColumns()))
    {
        disk->createDirectories(new_part_tmp_path);
        
        
        
        
        
        auto compression_codec = data.getCompressionCodecForPart(source_part->getBytesOnDisk(), source_part->ttl_infos, time_of_mutation);
        auto part_indices = getIndicesForNewDataPart(metadata_snapshot->getSecondaryIndices(), for_file_renames);
        auto part_projections = getProjectionsForNewDataPart(metadata_snapshot->getProjections(), for_file_renames);