Faceting large result sets in PostgreSQL

When it comes to query and searching interfaces, faceting is a useful feature for refining search results and making it easier for users to find what they are looking for.
It involves grouping search results into categories based on certain attributes (such as color, size, price, brand, and so on).
One common approach is to use a combination of indexing and filtering techniques to count the number of matching rows for each combination of facets, as shown in this article.