elasticsearch - 聚合中发现的Elasticsearch返回命中数

Question

我正在尝试从数据库中获取具有唯一“sku”字段的行。
我有一个可以正常计算此数字的查询，我的查询是:

GET _search
{
"size": 0,
"aggs": {
  "unique_products":{  
    "cardinality":{
      "field":"sku.keyword"
    }  
  }
},
"query": {
  "bool": {
    "must": [
      {
        "query_string": {
          "query": "(merch1: 'Dog') AND ((store_name: 'walmart')) AND product_gap: 'yes'"
        }
      },
      {
        "range": {
          "capture_date": {
            "format": "date",
            "gte": "2020-05-13",
            "lte": "2020-08-03"
          }
        }
      } 
    ]
  }
}

}

返回此结果:

{
  "took" : 129,
  "timed_out" : false,
  "_shards" : {
    "total" : 514,
    "successful" : 514,
    "skipped" : 98,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 150,
      "relation" : "eq"
    },
    "max_score" : null,
    "hits" : [ ]
  },
  "aggregations" : {
    "unique_products" : {
      "value" : 38
    }
  }
}

正确地将unique_products的数量报告为38。
我正在尝试编辑此查询，以便它实际上将返回所有38个独特的产品，但不确定如何，我首先尝试从agg结果返回最佳匹配:

GET _search
{
"size": 0,
"aggs": {
  "unique_products":{  
    "cardinality":{
      "field":"sku.keyword"
    }  
  },
  "top_hits": {
    "size": 1,
    "_source": {
      "include": [
        "sku", "source_store"
      ]
    }
  }
},
"query": {
  "bool": {
    "must": [
      {
        "query_string": {
          "query": "(merch1: 'Dog') AND ((store_name: 'walmart')) AND product_gap: 'yes'"
        }
      },
      {
        "range": {
          "capture_date": {
            "format": "date",
            "gte": "2020-05-13",
            "lte": "2020-08-03"
          }
        }
      } 
    ]
  }
}

}

但是我的结果有一个错误说:

{
  "error": {
    "root_cause": [
      {
        "type": "parsing_exception",
        "reason": "Expected [START_OBJECT] under [size], but got a [VALUE_NUMBER] in [top_hits]",
        "line": 10,
        "col": 13
      }
    ],
    "type": "parsing_exception",
    "reason": "Expected [START_OBJECT] under [size], but got a [VALUE_NUMBER] in [top_hits]",
    "line": 10,
    "col": 13
  },
  "status": 400
}

基数汇总仍然是我退回所有38种独特产品的最佳选择吗？谢谢

Answer 1

虽然基数聚合提供唯一计数，但它不能接受子聚合。换句话说，top_hits不能在这里直接使用。
该方法是正确的，但是您可能首先想对sku进行存储，然后使用top_hits检索基础文档:

{
  "size": 0,
  "aggs": {
    "unique_products": {
      "cardinality": {
        "field": "sku.keyword"
      }
    },
    "terms_agg": {
      "terms": {
        "field": "sku.keyword",
        "size": 100
      },
      "aggs": {
        "top_hits_agg": {
          "top_hits": {
            "size": 1,
            "_source": {
              "include": [
                "sku",
                "source_store"
              ]
            }
          }
        }
      }
    }
  },
  "query": {
    "bool": {
      "must": [
        {
          "query_string": {
            "query": "(merch1: 'Dog') AND ((store_name: 'walmart')) AND product_gap: 'yes'"
          }
        },
        {
          "range": {
            "capture_date": {
              "format": "date",
              "gte": "2020-05-13",
              "lte": "2020-08-03"
            }
          }
        }
      ]
    }
  }
}

仅供引用，您的查询引发异常的原因是 top_hits是agg 类型的agg ，就像 unique_products一样，它缺少自己的名称。