es - elasticsearch mapping - parameters - doc_values

世界上并没有完美的程序，但是我们并不因此而沮丧，因为写程序就是一个不断追求完美的过程。

问 ：doc_values有什么特点？
答 ：

问 ：doc_values如何使用？
答 ：

# doc_values
PUT /doc_values_test
{
  "mappings" : {
    "properties" : {
      "name1" : {"type" : "keyword"},
      "name2" : {
        "type"       : "keyword",
        "doc_values" : false
      }
    }
  }
}

# 索引
POST /doc_values_test/_doc/1
{
  "name1" : "hello",
  "name2" : "good"
}

# 索引
POST /doc_values_test/_doc/2
{
  "name1" : "good",
  "name2" : "hello"
}

# 搜索
GET /doc_values_test/_search
{
  "sort": [
    {
      "name1" : {
        "order" : "desc"
      }
    }
  ], 
  "aggs": {
    "agg_name1" : {
      "terms": {
        "field": "name1"
      }
    }
  }
}

# 结果
{
  "took" : 56,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 2,
      "relation" : "eq"
    },
    "max_score" : null,
    "hits" : [
      {
        "_index" : "doc_values_test",
        "_type" : "_doc",
        "_id" : "1",
        "_score" : null,
        "_source" : {
          "name1" : "hello",
          "name2" : "good"
        },
        "sort" : [
          "hello"
        ]
      },
      {
        "_index" : "doc_values_test",
        "_type" : "_doc",
        "_id" : "2",
        "_score" : null,
        "_source" : {
          "name1" : "good",
          "name2" : "hello"
        },
        "sort" : [
          "good"
        ]
      }
    ]
  },
  "aggregations" : {
    "agg_name1" : {
      "doc_count_error_upper_bound" : 0,
      "sum_other_doc_count" : 0,
      "buckets" : [
        {
          "key" : "good",
          "doc_count" : 1
        },
        {
          "key" : "hello",
          "doc_count" : 1
        }
      ]
    }
  }
}