Facets are extracted from the search result. Once a customer selects an option from the facet, we create a filter query that is typically an AND logic. For example, on searching for a particular item, say tommy hilfiger, we would be getting results that will have facets for size and color. It was previously assumed that the customer would select a single option from both the facets. Say the selections are medium for size and green for color. The filter query would be:

fq=clothes_size:medium&fq=clothes_color:green

This will be appended to our search query:

q=tommy%20hilfiger&qf=text%20cat^2%20name^2%20brand^2%20clothes_type^2%20clothes_color^2%20clothes_occassion^2&pf=text%20cat^3%20name^3%20brand^3%20clothes_type^3%20clothes_color^3%20clothes_occassion^3&fl=name,clothes_size,clothes_color,score&defType=edismax&facet=true&facet.mincount=1&facet.field=clothes_gender&facet.field=clothes_type&facet.field=clothes_size...