与汇总错误的总和

Question

我试图运行此查询：

GET my_index/_search
{
  "size": 0,
  "query": {
    "bool": {
      "filter": [
        {
          "query_string": {
            "query": "_exists_:products_count",
            "default_operator": "AND"
          }
        }
      ]
    }
  },
  "aggs": {
    "pid": {
      "terms": {
        "field": "pid",
        "size": 15,
        "order": {
          "products_counter": "ASC"
        }
      },
      "aggs": {
        "products_counter": {
          "sum": {
            "field": "products_count"
          }
        }
      }
    }
  }
}

我得到的结果是：

{
  "took": 5,
  "timed_out": false,
  "_shards": {
    "total": 12,
    "successful": 12,
    "failed": 0
  },
  "hits": {
    "total": 489681,
    "max_score": 0,
    "hits": []
  },
  "aggregations": {
    "pid": {
      "doc_count_error_upper_bound": -1,
      "sum_other_doc_count": 488443,
      "buckets": [
        {
          "key": 3229479298,
          "doc_count": 14,
          "products_counter": {
            "value": 26
          }
        },
        {...

虽然返回的pid的结果是188而不是26。 如果我将聚合的大小从15增加到100000，例如我得到正确的数字。 理解和解决我的问题有什么帮助？