Improve Faceting accuracy by having an option to count all records
For fields that have a large distinct value diversity, the faceting feature gives inaccurate results unless the count parameter is set to a number greater than the number of distinct values in a field. There should be an option in an index field that indicates to the search engine to count and facet all the values in a column. I realize this would hurt performance so it should be optional. But sometimes accuracy is more important than raw performance for consumers of your service.
Leonardo Sobrado commented
Additionally, a facet_count parameter would also be appropriate as discussed here: