How to return only aggregation stats in an ElasticSearch query?

Question

Is it possible to exclude documents from an aggregation query? I just need to know "count" and "sum" and do not need hits. I did it like this:

{
  "query": {
    "match_all": {

    }
  },
  "aggs": {
    "my_agg": {
      "stats": {
        "field": "country_id"
      }
    }
  }
}

Answer 1

To focus only on aggregation with a match_all query, you could simply use "size":0 (this specifies you want no query results) with no query:

curl -XPOST "http://localhost:9200/indexname/doctype/_search" -d'
{
    "size": 0, 
    "aggs": {
        "my_agg": {
            "stats": {
                "field": "country_id"
            }
        }
    }
}'