Elasticsearch - 不正确的聚合结果

Question

我试图在弹性搜索2.4.1上获得一个字段的最大值，但它与实际字段不同。

看起来ES正在进行近似聚合，但不确定最大值是否会出错。

执行时

POST http://192.168.100.211:9200/bt211/_search
{
  "size": 0,
  "query": {
    "match_all": {}
  },
  "aggs": {
    "grades_stats": {
      "max": {
        "field": "4999"
      }
    }
  }
} 

GOT

{
  "took": 4,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "failed": 0
  },
  "hits": {
    "total": 245831,
    "max_score": 0,
    "hits": [ ]
  },
  "aggregations": {
    "grades_stats": {
      "value": 4746809856
    }
  }
}

但是，如果我查询一个指定的文档

POST http://192.168.100.223:9200/bt211/_search
{
      "_source": [
        "4999"
      ],
      "query": {
        "terms": {
          "_id": [
            "AV5fg6y-7V3dJ49T89qT"
          ]
        }
      }
    }

它将回复

{
  "took": 238,
  "timed_out": false,
  "_shards": {
    "total": 5,
    "successful": 5,
    "failed": 0
  },
  "hits": {
    "total": 1,
    "max_score": 1,
    "hits": [
      {
        "_index": "bt211201709082",
        "_type": "test",
        "_id": "AV5fg6y-7V3dJ49T89qT",
        "_score": 1,
        "_source": {
          "4999": 4746809900
       }
     }
   ]
  }
}

“4999”的值为4746809900，大于“max”聚合的结果。

有没有办法在Elasticsearch中获得max的准确结果？