Feature Request: Statistics about metadata fields in search API

Overview of the Feature Request

We are interested in making statistics about metadata fields available through the search API.

Solr supports this via the stats and stats.field query parameters for indexed fields of numeric, string and date types: https://solr.apache.org/guide/6_6/the-stats-component.html

By default, Solr sends the following stats:

Example: If I pass the following query to Solr http://localhost:8983/solr/#/collection1/query?q=*:*&q.op=OR&indent=true&fq=publicationStatus:%22Published%22&fq=dvObjectType:%22datasets%22&stats=true&stats.field=resource.design.population.obtainedSampleSize I receive the following stats for the "obtained sample size" metadata field in addition to the query results:

"stats":{
    "stats_fields":{
      "resource.design.population.obtainedSampleSize":{
        "min":-1.0,
        "max":9.9999999E7,
        "count":25593,
        "missing":1540,
        "sum":1.41567565E8,
        "sumOfSquares":1.002115122884504E16,
        "mean":5531.495526120423,
        "stddev":625733.9594302336
      }
    }
  }

This feature could be implemented relatively easily by allowing the search API user to pass a stats.field parameter into Solr, and passing the output back.

What kind of user is the feature intended for?

API users

What inspired the request?

In our custom UI, we have a range input for searches on numeric fields. For the input, we would like to know the min and max of the fields to use as the default min and max of the input.

Example: numeric field "obtained sample size"

What existing behavior do you want changed?

/

Any brand new behavior do you want to add to Dataverse?

Any open or closed issues related to this feature request?

Didn't find any

Are you thinking about creating a pull request for this feature?

Yes

Start with the search API and the linked Solr Stats Component documentation, focusing on how query parameters and Solr responses are currently handled. Done means API users can provide stats.field and receive the corresponding field statistics alongside search results, including the numeric-field min and max needed by the requested range input.