4 ms·

Also, > `repo_name` LowCardinality(String), This is not a low cardinality: 7133122498 = 7.1B Don't use low cardinality for such columns!

• zX41ZdbW 3y ago
  The LowCardinality data type does not require the whole set of values to have a low cardinality. It benefits when the values have locally low cardinality. For example, if the number of unique values in `repo_name` is a hundred million, but for every million consecutive values, there are only ten thousand unique, it will give a great speed-up.
  • zx8080 3y ago
    > LowCardinality data type does not require the whole set of values to have a low cardinality. Don't mislead others. It's not true unless low_cardinality_max_dictionary_size is set to some other value than the default one: 8192. It does not work well for hundred million values.