`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...`
const MergeTreeData::DataPartPtr & part,
    const StorageMetadataPtr & metadata_snapshot,
    const KeyCondition & key_condition,
    const Settings & settings,
    Poco::Logger * log)
{
    MarkRanges res;
    size_t marks_count = part->index_granularity.getMarksCount();
    const auto & index = part->index;
    if (marks_count == 0)
        return res;
    bool has_final_mark = part->index_granularity.hasFinalMark();
    
    if (key_condition.alwaysUnknownOrTrue())
    {
        LOG_TRACE(log, "Not using primary index on part {}", part->name);
        if (has_final_mark)
            res.push_back(MarkRange(0, marks_count - 1));
        else
            res.push_back(MarkRange(0, marks_count));
        return res;
    }
    size_t used_key_size = key_condition.getMaxKeyColumn() + 1;
    std::function<void(size_t, size_t, FieldRef &)> create_field_ref;
    
    
    const auto & primary_key = metadata_snapshot->getPrimaryKey();
    if (key_condition.hasMonotonicFunctionsChain())
    {
        auto index_block = std::make_shared<Block>();