Elasticsearch 取平均值

Question

我正在尝试对 elasticsearch 上的聚合数据进行平均。这是我的数据结构：

文档 1

{
   "groupId":"TEST_01",
   "lag":10,
   "detectionDate":"2021-02-26T21:42:30.010Z",
   "tipo":"uno",
   "topics":[
      {
         "name":"topic_01",
         "valore":2
      },
      {
         "name":"topic_02",
         "valore":4
      }
   ]
}

文档 2

{
   "groupId":"TEST_01",
   "lag":10,
   "detectionDate":"2021-02-26T21:42:30.010Z",
   "tipo":"uno",
   "topics":[
      {
         "name":"topic_01",
         "valore":4
      },
      {
         "name":"topic_02",
         "valore":8
      }
   ]
}

我必须通过 groupId 和主题名称创建一个聚合，并在此聚合上计算值字段的平均值。但是用源码试了一下求平均值的结果是错误的

根据文件一和文件二的上述数据，预期结果应该是：

groupId	topicName	average
TEST_01	topic_01	3
TEST_01	topic_02	6

TermsAggregationBuilder aggregation = AggregationBuilders
    .terms("groupId")
    .field("groupId.keyword")
        .subAggregation(AggregationBuilders
            .terms("topicName")
            .field("topics.name.keyword").subAggregation(AggregationBuilders
                .avg("avg").field("topics.valore")));

Answer 1

首先确保您的主题字段类型为“嵌套”，因为如果它是“对象”，则 topicName 和 valores 将被展平。这意味着您最终将得到一组价值和主题名称，它们之间没有关系。

映射

{
  "test_ynsanity" : {
    "mappings" : {
      "properties" : {
        "detectionDate" : {
          "type" : "date"
        },
        "groupId" : {
          "type" : "text",
          "fields" : {
            "keyword" : {
              "type" : "keyword",
              "ignore_above" : 256
            }
          }
        },
        "lag" : {
          "type" : "long"
        },
        "tipo" : {
          "type" : "text",
          "fields" : {
            "keyword" : {
              "type" : "keyword",
              "ignore_above" : 256
            }
          }
        },
        "topics" : {
          "type" : "nested",
          "properties" : {
            "name" : {
              "type" : "text",
              "fields" : {
                "keyword" : {
                  "type" : "keyword",
                  "ignore_above" : 256
                }
              }
            },
            "valore" : {
              "type" : "long"
            }
          }
        }
      }
    }
  }
}

正在摄取数据

POST test_ynsanity/_doc
{
   "groupId":"TEST_01",
   "lag":10,
   "detectionDate":"2021-02-26T21:42:30.010Z",
   "tipo":"uno",
   "topics":[
      {
         "name":"topic_01",
         "valore":2
      },
      {
         "name":"topic_02",
         "valore":4
      }
   ]
}

POST test_ynsanity/_doc
{
   "groupId":"TEST_01",
   "lag":10,
   "detectionDate":"2021-02-26T21:42:30.010Z",
   "tipo":"uno",
   "topics":[
      {
         "name":"topic_01",
         "valore":4
      },
      {
         "name":"topic_02",
         "valore":8
      }
   ]
}

查询

POST test_ynsanity/_search
{
  "size": 0, 
  "aggs": {
    "groups": {
      "terms": {
        "field": "groupId.keyword",
        "size": 10
      },
      "aggs": {
        "topics": {
          "nested": {
            "path": "topics"
          },
          "aggs": {
            "topic_names": {
              "terms": {
                "field": "topics.name.keyword"
              },
              "aggs": {
                "topic_avg": {
                  "avg": {
                    "field": "topics.valore"
                  }
                }
              }
            }
          }
        }
      }
    }
  }
}

回应

{
  "took" : 1,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 2,
      "relation" : "eq"
    },
    "max_score" : null,
    "hits" : [ ]
  },
  "aggregations" : {
    "groups" : {
      "doc_count_error_upper_bound" : 0,
      "sum_other_doc_count" : 0,
      "buckets" : [
        {
          "key" : "TEST_01",
          "doc_count" : 2,
          "topics" : {
            "doc_count" : 4,
            "topic_names" : {
              "doc_count_error_upper_bound" : 0,
              "sum_other_doc_count" : 0,
              "buckets" : [
                {
                  "key" : "topic_01",
                  "doc_count" : 2,
                  "NAME" : {
                    "value" : 3.0
                  }
                },
                {
                  "key" : "topic_02",
                  "doc_count" : 2,
                  "NAME" : {
                    "value" : 6.0
                  }
                }
              ]
            }
          }
        }
      ]
    }
  }
}

我现在无法访问 Java DSL，但查询应该如下所示：

TermsAggregationBuilder aggregation = AggregationBuilders
    .terms("groupId")
    .field("groupId.keyword")
        .subAggregation(AggregationBuilders
            .nested("agg", "topics")
            .terms("topic_names")
            .field("topics.name.keyword").subAggregation(AggregationBuilders
                .avg("avg").field("topics.valore")));

Elasticsearch 取平均值

Elasticsearch get average

elasticsearch

elasticsearch-java-api

elasticsearch-aggregation