Has Child Query

The has_child query works the same as the has_child filter, by automatically wrapping the filter with a constant_score. It has the same syntax as the has_child filter:

{
    "has_child" : {
        "type" : "blog_tag"
        "query" : {
            "term" : {
                "tag" : "something"
            }
        }
    }
}

Scope

A _scope can be defined on the filter allowing to run facets on the same scope name that will work against the child documents. For example:

{
    "has_child" : {
        "_scope" : "my_scope",
        "type" : "blog_tag"
        "query" : {
            "term" : {
                "tag" : "something"
            }
        }
    }
}

Memory Considerations

With the current implementation, all _id values are loaded to memory (heap) in order to support fast lookups, so make sure there is enough mem for it.