es - elasticsearch - aggs - bucket - rare

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：rare_terms有什么特点？
答：

问：rare_terms如何使用？
答：

# 删除
DELETE /rare_terms_test

# 映射
PUT /rare_terms_test
{
  "mappings": {
    "properties": {
      "name": {"type": "keyword"}
    }
  }
}

# 索引
POST /rare_terms_test/_bulk?routing=1&refresh
{"index": {"_id": 1}}
{"name": "hello"}
{"index": {"_id": 2}}
{"name": "good"}
{"index": {"_id": 3}}
{"name": "me"}
{"index": {"_id": 4}}
{"name": "hello"}
{"index": {"_id": 5}}
{"name": "hello"}
{"index": {"_id": 6}}
{"name": "hello"}
{"index": {"_id": 7}}
{"name": "good"}
{"index": {"_id": 8}}
{"name": "kitty"}





# 搜索
GET /rare_terms_test/_search?size=0
{
  "aggs": {
    "rare_terms_aggs": {
      "rare_terms": {
        "field": "name",
        "max_doc_count": 2,
        "include": ["hello", "good", "me"],
        "exclude": ["kitty"]
      }
    }
  }
}

# 结果
{
  "took" : 1,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 8,
      "relation" : "eq"
    },
    "max_score" : null,
    "hits" : [ ]
  },
  "aggregations" : {
    "rare_terms_aggs" : {
      "buckets" : [
        {
          "key" : "me",
          "doc_count" : 1
        },
        {
          "key" : "good",
          "doc_count" : 2
        }
      ]
    }
  }
}