es - elasticsearch - aggs - pipeline - avg

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：avg_bucket有什么特点？
答：

问：avg_bucket如何使用？
答：

DELETE /avg_bucket_test

PUT /avg_bucket_test
{
  "mappings": {
    "properties": {
      "type": {"type": "integer"},
      "num": {"type": "integer"}
    }
  }
}

POST /avg_bucket_test/_bulk
{"index": {"_id": 1}}
{"type": 1, "num": 3}
{"index": {"_id": 2}}
{"type": 2, "num": 7}
{"index": {"_id": 3}}
{"type": 1, "num": 5}
{"index": {"_id": 4}}
{"type": 2, "num": 9}
{"index": {"_id": 5}}
{"type": 1, "num": 6}

GET /avg_bucket_test/_search
{
  "size": 0,
  "aggs": {
    "avg_num_aggs": {
      "terms": {
        "field": "type",
        "size": 2
      },
      "aggs": {
        "sum_num_aggs": {
          "sum": {
            "field": "num"
          }
        }
      }
    },
    "avg_num_bucket_aggs": {
      "avg_bucket": {
        "buckets_path": "avg_num_aggs>sum_num_aggs"
      }
    }
  }
}

# 结果
{
  "took" : 1,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 5,
      "relation" : "eq"
    },
    "max_score" : null,
    "hits" : [ ]
  },
  "aggregations" : {
    "avg_num_aggs" : {
      "doc_count_error_upper_bound" : 0,
      "sum_other_doc_count" : 0,
      "buckets" : [
        {
          "key" : 1,
          "doc_count" : 3,
          "sum_num_aggs" : {
            "value" : 14.0
          }
        },
        {
          "key" : 2,
          "doc_count" : 2,
          "sum_num_aggs" : {
            "value" : 16.0
          }
        }
      ]
    },
    "avg_num_bucket_aggs" : {
      "value" : 15.0
    }
  }
}