Major Description
Now that range faceting supports a "filter" and a "dv" method, and that interval faceting is supported on fields with docValues=false, I think we should make it so that interval faceting is just a different way of specifying ranges in range faceting, allowing users to indicate specific ranges.
I propose we use the same syntax for intervals, but under the "range" parameter family:
facet.range=price& f.price.facet.range.set=[0,10]& f.price.facet.range.set=(10,100]
The counts for those ranges would come in the response also inside of the "range_facets" section. I'm not sure if it's better to include the ranges in the "counts" section, or in a different section (intervals?sets?buckets?). I'm open to suggestions.
"facet_ranges":{ "price":{ "counts":[ "[0,10]",3, "(10,100]",2] } }
or…
"facet_ranges":{ "price":{ "intervals":[ "[0,10]",3, "(10,100]",2] } }
We should support people specifying both things on the same field.
Once this is done, "interval faceting" could be deprecated, as all it's functionality is now possible through range queries.