mapping = {
      "my_index": {
        "date_detection": False,
        "dynamic_templates": [{
          "string_fields": {
            "mapping": {
              "type": "string",
              "fields": {
                "raw": {
                  "index": "not_analyzed",
                  "ignore_above": 256,
                  "type": "string"
                }
              }
            },
            "match_mapping_type": "string",
            "match": "*"
          }
        }]
      }
    }

records = es.search(index="my_index",doc_type="marksheet",body={ "aggs": { "student_name": { "terms": { "field": "name.raw","order": { "total_score" : "desc" } }, "aggs": { "total_score": { "sum": { "field": "score" } } } } } } )