Looking at my mappings I'm often seeing something like this. I expect to see a flat country_iso_code having type text, but what is the keyword field? I don't see this in the raw data, I just see a country code value. Could it be that some of the data, which is machine-generated, has a nested structure? Thanks
It's automatically generated by elasticsearch because you did not define a mapping.
It helps you in case you want to sort on country_iso_code.keyword or compute aggregations on it, which you can't do on country_iso_code.
Thanks! So, does that mean there would be an explicit field called 'keyword' or country_iso_code.keyword? I don't see any evidence that my data source ever generated a field called country_iso_code.keyword. Also, I can't find what you're talking about in the documentation for mapping.