Hi, Issues(LUCENE-4795): Add FacetsCollector based on SortedSetDocValues
https://issues.apache.org/jira/browse/LUCENE-4795 i) In the above discussion, mentioned that there is no need to maintain sidecar index to collect facets & its count (FacetsCollector) and even we can achieve it in flat index using SortedSetDocValues... Then what is the main benefits of using Sidecar or Taxonomy index? ii)And i tried to achieve multilevel (hierarchical) categorization using SortedSetDocValues and got it simply by changing the query and opening the IndexReader for each level of query using SortedSetDocValuesReaderState.. And i know, in SortedSetDocValuesFacetField > > > - Faceting is a bit slower (~25%), and there is added cost on > every IndexReader open to create a new SortedSetDocValuesReaderState. > > > - does not support hierarchical facets > > 1. what are the functionalities we will be missing when we use SortedSetDocValues for faceting? what is hierarchical facets? what can we achieve using hierarchical facets? 2. Except faster faceting and supporting hierarchical facets, is there any benefit of using taxonomy index over docvalues field for faceting? Any ideas/help/recommendations greatly appreciated.. Regards, Chitra
