To anyone using the JSON Facet API in released Solr versions: I discovered a serious memory leak while doing performance benchmarks (see http://yonik.com/facet_performance/ for some of the early results).
Assuming you're in the evaluation / development phase of your project, I'd recommend using a recent developer snapshot for now: https://builds.apache.org/job/Solr-Artifacts-5.x/lastSuccessfulBuild/artifact/solr/package/ The fix (and performance improvements) will also be in the next Solr release (5.3) of course. -Yonik
