Terms Stats Facet

The terms_stats facet combines both the terms and statistical allowing to compute stats computed on a field, per term value driven by another field. For example:

{
    "query" : {
        "match_all" : {  }
    },
    "facets" : {
        "tag_price_stats" : {
            "terms_stats" : {
                "key_field" : "tag",
                "value_field" : "price"
            }
        }
    }
}

The size parameter controls how many facet entries will be returned. It defaults to 10. Setting it to 0 will return all terms matching the hits (be careful not to return too many results).

One can also set shard_size (in addition to size) which will determine how many term entries will be requested from each shard. When dealing with field with high cardinality (at least higher than the requested size) The greater shard_size is - the more accurate the result will be (and the more expensive the overall facet computation will be). shard_size is there to enable you to increase accuracy yet still avoid returning too many terms_stats entries back to the client.

Ordering is done by setting order, with possible values of term, reverse_term, count, reverse_count, total, reverse_total, min, reverse_min, max, reverse_max, mean, reverse_mean. Defaults to count.

The value computed can also be a script, using the value_script instead of value_field, in which case the lang can control its language, and params allow to provide custom parameters (as in other scripted components).

Note, the terms stats can work with multi valued key fields, or multi valued value fields, but not when both are multi valued (as ordering is not maintained).