获取 date_histogram 的桶平均值，elasticsearch

Question

我有以下查询，从中获取数据并创建过去每个小时的聚合：

    query = {
        "query": {
            "bool": {          
                "must": [
                    { "term": {"deviceId":device} },
                    { "match": {"eventType":"Connected"} } 
                ],
                "must_not":[{
                        "query_string": {
                            "query": "Pong",
                            "fields": ["data.message"]
                        }
                    },
                ] 
            },

        },
        "size": 0,
        "sort": [{ "timestamp": { "order": "desc" }}],
        "aggs" : {
            "time_buckets" : {
                "date_histogram" : {
                    "field" : "timestamp",
                    "interval" : "hour",

                },
            }
        }
    }

我想从每个小时间隔（聚合创建的每个存储桶）中获取字段的平均值。在这篇文章中，他们谈论的事情与我想做的类似： http://www.elasticsearch.org/guide/en/elasticsearch/guide/current/_looking_at_time.html ("What was the average latency of our website every hour in the last week?")。但是，他们并没有具体说明在这种情况下该怎么做。

有人知道怎么做吗？

Answer 1

刚刚意识到我可以进行嵌套聚合，然后计算聚合内某个字段的平均值。这是我所做的，现在可以正常工作了：

 query = {
            "query": {
                "bool": {          
                    "must": [
                        { "term": {"deviceId":device} },
                        { "match": {"eventType":"Connected"} } 
                    ],
                    "must_not":[{
                            "query_string": {
                                "query": "Pong",
                                "fields": ["data.message"]
                            }
                        },
                    ] 
                },

            },
            "size": 0,
            "sort": [{ "timestamp": { "order": "desc" }}],
            "aggs" : {
                "time_buckets" : {
                    "date_histogram" : {
                        "field" : "timestamp",
                        "interval" : "day"
                    },
                    "aggs" : {
                        "avg_battery" : {
                            "avg": { "field": "data.battery-level" } 
                        }
                    }
                }
            }
        }