Hi The reason IMO is historic - ES and Solr had faceting solutions before Lucene had it. There were discussions in the past about using the Lucene faceting module in Solr (can't tell for ES) but, sadly, I can't say I see it happening at this point.
Regarding your other question, IMO the Lucene faceting engine, in terms of performance and customizability, is on par with Solr/ES. However, it lacks distributed faceting support and aggregations. Since many people use Solr/ES and not Lucene directly, the Solr/ES faceting module continues to advance separately from the Lucene one. Enhancing Lucene facets with aggregations and even distributed faceting capabilities is mostly a matter of time and priorities. If you're interested in it, I'd be willing to collaborate with you on that as much as I can! And I'd still hope that this work finds its way into Solr/ES, as I think it's silly to have that many number of faceting implementations, where they all rely on the same low-level data structure - Lucene! Shai On Thu, Nov 10, 2016 at 12:32 PM Kumaran Ramasubramanian <kums....@gmail.com> wrote: > Hi All, > We all know that Lucene supports faceting by providing > Taxonomy(Separate index and hierarchical facets) and > SortedSetDocValuesFacetField ( flat facets and no sidecar index). > > Then why did solr and elastic search go for its own implementation ? > ( that is, solr uses block join & elasticsearch uses aggregations ) Is > there any limitations in lucene's implementation ? > > > -- > Kumaran R >
