I tried running with the LRUStatsCache for global IDF, but the performance penalty was pretty big. The 95th percentile response time went from 3.4 seconds to 13 seconds. Oops.
We should not need a separate call to get the tf and df stats. Those are already calculated when doing the first request. I worked on a search engine that did it that way twenty years ago. In the past, there would have been an IP obstacle, but I think that is resolved. wunder Walter Underwood wun...@wunderwood.org http://observer.wunderwood.org/ (my blog)
