Faceted searches break up the search results into multiple categories, showing counts for each category. Faceting is used in searches to drill down into a subset of results from a query. To get an idea of how facets are helpful, let us go to www.amazon.com and search for mobile phones. We will see facets on the left-hand side such as brand, display size, and carrier. Once we select a facet to drill down, we will see more facets that will help us narrow down the phone we would like to purchase.
Faceting is generally done on human readable text that is predefined such as location, price, and author name. It would not make sense tokenizing these fields. So, facet fields are kept separate from search and sorting fields in the Solr schema. They are also not converted to lowercase but are kept as they are. Faceting is done on indexed fields on Solr. So there is no need to store faceted fields.
Solarium introduces the concept of facetset, which is one central component and can be used to...