Use stats

With stats, we can have Solr calculate statistics on numerical values (such as size).

• https://arcticdata.io/metacat/d1/mn/v2/query/solr/?q=formatType:DATA&stats=true&stats.field=size&rows=0

This query calculates a set of summary statistics for the size field on data objects that Solr has indexed. In this case, Solr’s size field indexes the size field in the system metadata for each object in Metacat.