elasticsearch - Elasticsearch Minimum Aggreviate返回null

Question

我有一个名为“posts”的elasticsearch索引。
http://127.0.0.1:9200/posts/doc/_count返回{"count":240000,"_shards":{"total":5,"successful":5,"skipped":0,"failed":0}}。

我正在尝试在“doc”类型中找到最低ID字段。谷歌搜索后，我相信我想要的工具是聚合。

大部分直接从official documentation复制和粘贴后，我开始使用它:

POST /posts/_search?size=0
{
    "aggs" : {
        "min_id" : { "min" : { "field" : "id" } }
    }
}

使用 curl -X POST "localhost:9200/posts/_search?size=0" -H 'Content-Type: application/json' -d'{"aggs" : {"min_id" : { "min" : { "field" : "id" } }}}'提交请求。
结果如下:

{
  "took" : 0,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : 240000,
    "max_score" : 0.0,
    "hits" : [ ]
  },
  "aggregations" : {
    "min_id" : {
      "value" : null
    }
  }
}

我相信 min_id的值不应为null。

当我搜索size = 1时，得到以下信息:

{
  "took" : 2,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : 240000,
    "max_score" : 1.0,
    "hits" : [
      {
        "_index" : "posts",
        "_type" : "doc",
        "_id" : "1733768",
        "_score" : 1.0,
        "_source" : {
          "doc" : {
            "id" : 1733768,
            "description" : "",
            "ext" : "png",
            "tags" : [],
            ...
          }
        }
      }
    ]
  },
  "aggregations" : {
    "min_id" : {
      "value" : null
    }
  }
}

我究竟做错了什么？

Answer 1

差不多了，您犯了一个小错误，id字段位于doc对象结构内部，因此您需要查询doc.id而不是id，如下所示:

POST /posts/_search?size=0
{
    "aggs" : {
        "min_id" : { "min" : { "field" : "doc.id" } }
                                           ^
                                           |
                                        add this
    }
}