`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...`
Processors processors;
        std::vector<OutputPorts::iterator> output_ports;
        processors.reserve(ports.size() + num_streams);
        output_ports.reserve(ports.size());
        for (auto & port : ports)
        {
            auto copier = std::make_shared<CopyTransform>(header, num_streams);
            connect(*port, copier->getInputPort());
            output_ports.emplace_back(copier->getOutputs().begin());
            processors.emplace_back(std::move(copier));
        }
        for (size_t i = 0; i < num_streams; ++i)
        {
            auto merge = get_merging_processor();
            merge->setSelectorPosition(i);
            auto input = merge->getInputs().begin();
            
            for (size_t j = 0; j < ports.size(); ++j)
            {
                connect(*output_ports[j], *input);
                ++output_ports[j];
                ++input;
            }
            processors.emplace_back(std::move(merge));
        }
        return processors;
    });
    return pipe;
}
MarkRanges MergeTreeDataSelectExecutor::markRangesFromPKRange(