This feature implements group counts, also known as facets, which are frequently used in e-commerce or catalog applications. In various applications, it is preferable not only to display the list of hits returned by a query, but also to categorize the results.

For example, an e-commerce application wants to display all products matching a query for the term management along with faceting information. The facets include ‘type of product’ (books or DVDs), ‘author’, and ‘date’. For each facet, the application displays the unique values (books or DVDs) and their counts. You can quickly assess that most of the product offerings of interest fall under the ‘books’ category. You can further refine the search by selecting the ‘books’ value under ‘type of product’.

A group count is defined as the number of documents that have a certain value. If a value is repeated within the same document, the document contributes a count of 1 to the total group count for the value. Group counts or facets are supported for SDATA sections that use optimized_for search SDATA. To request a computation of facets for a query, use the Result Set Interface.