Filter

When doing things like facet navigation, sometimes only the hits are needed to be filtered by the chosen facet, and all the facets should continue to be calculated based on the original query. The filter element within the search request can be used to accomplish it.

Note, this is different compared to creating a filtered query with the filter, since this will cause the facets to only process the filtered results.

For example, lets create two tweets, with two different tags:

curl -XPUT 'localhost:9200/twitter/tweet/1' -d '
{
    "message" : "something blue",
    "tag" : "blue"
}
'

curl -XPUT 'localhost:9200/twitter/tweet/2' -d '
{
    "message" : "something green",
    "tag" : "green"
}
'

curl -XPOST 'localhost:9200/_refresh'

We can now search for something, and have a terms facet.

curl -XPOST 'localhost:9200/twitter/_search?pretty=true' -d '
{
    "query" : {
        "term" : { "message" : "something" }
    },
    "facets" : {
        "tag" : {
            "terms" : { "field" : "tag" }
        }
    }
}
'

We get two hits, and the relevant facets with a count of 1 for both green and blue. Now, lets say the green facet is chosen, we can simply add a filter for it:

curl -XPOST 'localhost:9200/twitter/_search?pretty=true' -d '
{
    "query" : {
        "term" : { "message" : "something" }
    },
    "filter" : {
        "term" : { "tag" : "green" }
    },
    "facets" : {
        "tag" : {
            "terms" : { "field" : "tag" }
        }
    }
}
'

And now, we get only 1 hit back, but the facets remain the same.

Note, if additional filters is required on specific facets, they can be added as a facet_filter to the relevant facets.