While querying Elasticsearch, it’s a good practice to restrict your search results to only the fields you need.

To include only specific fields in an Elasticsearch query, use source filtering:

GET /_search
{
    "_source": {        
        "include": ["title", "country"]
    },
    "query" : {
        "term" : { "country" : "france" }
    }
}

You can also do source filtering using a GET parameter.

curl "localhost:9200/<index>/_doc/1?_source_includes=title,country"

NOTE: you can also exclude specific fields in a search response.