And waits for them. That's pointless.
MergeTreeData::DataPartPtr source_part, const MutationCommands & commands_for_removes, const String & mrk_extension)
{
    
    std::map<String, size_t> stream_counts;
    for (const NameAndTypePair & column : source_part->getColumns())
    {
        auto serialization = source_part->getSerializationForColumn(column);
        serialization->enumerateStreams(
            [&](const ISerialization::SubstreamPath & substream_path)
            {
                ++stream_counts[ISerialization::getFileNameForStream(column, substream_path)];
            },
            {});
    }
    NameToNameVector rename_vector;
    
    for (const auto & command : commands_for_removes)
    {
        if (command.type == MutationCommand::Type::DROP_INDEX)
        {
            if (source_part->checksums.has(INDEX_FILE_PREFIX + command.column_name + ".idx"))
            {
                rename_vector.emplace_back(INDEX_FILE_PREFIX + command.column_name + ".idx", "");
                rename_vector.emplace_back(INDEX_FILE_PREFIX + command.column_name + mrk_extension, "");
            }
        }
        else if (command.type == MutationCommand::Type::DROP_PROJECTION)
        {
            if (source_part->checksums.has(command.column_name + ".proj"))
                rename_vector.emplace_back(command.column_name + ".proj", "");