`Selected 13 parts by date, 13 parts by key, 26 marks by primary key .... `

This message is confusing for new users.

I suggest to replace it with

`Selected 13 parts by partition key, 13 parts by primary key, 26 marks by primary key...`
case MergeTreeData::MergingParams::VersionedCollapsing:
                return std::make_shared<VersionedCollapsingTransform>(header, pipe.numOutputPorts(),
                           sort_description, data.merging_params.sign_column, max_block_size);
            case MergeTreeData::MergingParams::Graphite:
                throw Exception("GraphiteMergeTree doesn't support FINAL", ErrorCodes::LOGICAL_ERROR);
        }
        __builtin_unreachable();
    };
    if (num_streams > settings.max_final_threads)
        num_streams = settings.max_final_threads;
    if (num_streams <= 1 || sort_description.empty())
    {
        pipe.addTransform(get_merging_processor());
        return pipe;
    }
    ColumnNumbers key_columns;
    key_columns.reserve(sort_description.size());
    for (auto & desc : sort_description)
    {
        if (!desc.column_name.empty())
            key_columns.push_back(header.getPositionByName(desc.column_name));
        else
            key_columns.emplace_back(desc.column_number);
    }
    pipe.addSimpleTransform([&](const Block & stream_header)
    {
        return std::make_shared<AddingSelectorTransform>(stream_header, num_streams, key_columns);
    });
    pipe.transform([&](OutputPortRawPtrs ports)
    {