Shawn, I've been thinking along your lines, and continued to run tests through the day. The results surprised me.
For my index, Solr range faceting time is most closely related to the total number of documents in the index for the range specified. The number of "buckets" in the range is a second factor. I found NO correlation whatsoever to the number of hits in the query. Whether I have 3 hits or 1,500,000 hits, it's ~24 seconds to facet the result for that same time period. That is what surprised me. For example, if my facet range is a 10 year period for which there exists 47M docs in the index, the facet time is 24 seconds. If I switch my facet range to a different 10 year period with 1.3M docs, the facet time drops to less than 5 seconds. If I go back to my original 10 year period (with 47M docs in the index), but facet by month instead of day, my facet time drops to 2.5 seconds. Now, I can't meet my user needs this way, but it does show the relationship between # of buckets and faceting time. Regards, David
