es - elasticsearch - aggs - metrics - scripted

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：scripted_metrc有什么特点？
答：

问：scripted_metric如何使用？
答：

DELETE /scripted_metric_test

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

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


GET /scripted_metric_test/_search
{
  "size": 0,
  "aggs": {
    "scripted_metric_aggs": {
      "scripted_metric": {
        "init_script": "state.cals=[]",
        "map_script": "state.cals.add(doc.type.value == 1 ? doc.num.value * params.param1 : doc.num.value * params.param2)",
        "combine_script": "int sum = 0; for (n in state.cals) { sum += n } return sum",
        "reduce_script": "int fsum = 0; for (s in states) {fsum += s } return fsum",
        "params": {
          "param1": 3,
          "param2": 5
        }
      }
    }
  }
}

# 结果
{
  "took" : 16,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 5,
      "relation" : "eq"
    },
    "max_score" : null,
    "hits" : [ ]
  },
  "aggregations" : {
    "scripted_metric_aggs" : {
      "value" : 107
    }
  }
}