[LUCENE-7927] Add facets impl to count unique numeric values

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 7.1, 8.0
• Component/s: modules/facet
• Lucene Fields: New
• Assignee: Michael McCandless
• Reporter: Michael McCandless
• Created: 10/Aug/17 20:25
• Updated: 28/Aug/22 15:18
• Resolved: 16/Oct/17 10:33

Description

The facets module has multiple facet methods for counting flat and hierarchical fields, and also a method for counting numeric ranges. I'd like to also add a method that counts unique numeric (long) values, designed to be used for fields that have only a few, typically low valued, numbers across the index e.g. a "review" rating from 1 to 5.