es - elasticsearch - aggs - bucket - variable

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：variable_width_histogram有什么特点？
答：

问：variable_width_histogram如何使用？
答：

# 删除
DELETE /variable_width_histogram_test

# 映射
PUT /variable_width_histogram_test
{
  "mappings": {
    "properties": {
      "name": {"type": "keyword"},
      "filter_type": {"type": "keyword"},
      "num": {"type": "integer"}
    }
  }
}

# 索引
POST /variable_width_histogram_test/_bulk?routing=1&refresh
{"index": {"_id": 1}}
{"name": "hello", "filter_type": "t1", "num": 3}
{"index": {"_id": 2}}
{"name": "me", "filter_type": "t2", "num": 5}
{"index": {"_id": 3}}
{"name": "me", "filter_type": "t1", "num": 18}
{"index": {"_id": 4}}
{"name": "hello", "filter_type": "t1", "num": 20}
{"index": {"_id": 5}}
{"name": "good", "filter_type": "t1", "num": 28}
{"index": {"_id": 6}}
{"name": "me", "filter_type": "t2", "num": 50}
{"index": {"_id": 7}}
{"name": "good", "filter_type": "t1", "num": 58}
{"index": {"_id": 8}}
{"name": "hello", "filter_type": "t1", "num": 88}

# 搜索
GET /variable_width_histogram_test/_search?size=0
{
  "aggs": {
    "variable_width_histogram_aggs": {
      "variable_width_histogram": {
        "field": "num",
        "buckets": 4
      }
    }
  }
}

# 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" : {
    "variable_width_histogram_aggs" : {
      "buckets" : [
        {
          "min" : 3.0,
          "key" : 4.0,
          "max" : 5.0,
          "doc_count" : 2
        },
        {
          "min" : 18.0,
          "key" : 22.0,
          "max" : 28.0,
          "doc_count" : 3
        },
        {
          "min" : 50.0,
          "key" : 54.0,
          "max" : 58.0,
          "doc_count" : 2
        },
        {
          "min" : 88.0,
          "key" : 88.0,
          "max" : 88.0,
          "doc_count" : 1
        }
      ]
    }
  }
}