Faceting

Elasticsearch is a full-text search engine that aims to provide search results on the basis of our queries. However, sometimes we would like to get more—for example, we would like to get aggregated data that is calculated on the result set we get, such as the number of documents with a price between 100 and 200 dollars or the most common tags in the result documents. In the Aggregations section of this chapter, we talked about the aggregations framework. In addition to this, Elasticsearch provides a faceting module that is responsible for providing the functionality we've mentioned. In this chapter, we will discuss different faceting methods provided by Elasticsearch.

Note

Note that faceting offers a subset of functionality provided by the aggregation module. Because of this, Elasticsearch creators would like all the users to migrate from faceting to the mentioned aggregation module. Faceting is not deprecated and you can use it, but beware that sometime in the future, it may be removed...