弹性搜索中嵌套元素的频率计数聚合返回零结果

Question

我正在尝试进行聚合查询以计算嵌套在弹性搜索中的元素数量。这是映射的一部分：

 {
  "news" : {
    "aliases" : { },
    "mappings" : {
      "dynamic" : "false",
      "properties" : {
        "categories" : {
          "type" : "nested",
          "properties" : {
            "categoryId" : {
              "type" : "text"
            },
            "name" : {
              "type" : "text"
            },
            "slug" : {
              "type" : "text"
            }
          }
        }
      }
    }
  }
}

这是我做的查询：

{   
    "size": 0,
    "aggs":{
        "categories_count":{
            "terms": {
                "field":"categories.slug.keyword",
                "size": 100
            }
        }
    }
}

这是我得到的结果：

{
    "took": 8,
    "timed_out": false,
    "_shards": {
        "total": 1,
        "successful": 1,
        "skipped": 0,
        "failed": 0
    },
    "hits": {
        "total": {
            "value": 22,
            "relation": "eq"
        },
        "max_score": null,
        "hits": []
    },
    "aggregations": {
        "categories_count": {
            "doc_count_error_upper_bound": 0,
            "sum_other_doc_count": 0,
            "buckets": []
        }
    }
}

这是我想要实现的目标： 说有两个文件：

doc 1 类别：

"categories" : [
      {
        "categoryId" : "aaaaffff",
        "name" : "Category 1",
        "slug" : "category-1",
      },
      {
        "categoryId" : "aaaafffd",
        "name" : "Category 2",
        "slug" : "category-2",
      },
      {
        "categoryId" : "aaaafffc",
        "name" : "Category 3",
        "slug" : "category-3",
      }
    ],

文档 2 类别：

"categories" : [
          {
            "categoryId" : "aaaafffd",
            "name" : "Category 2",
            "slug" : "category-2",
          },
          {
            "categoryId" : "aaaafffc",
            "name" : "Category 3",
            "slug" : "category-3",
          },
          {
            "categoryId" : "aaaafffb",
            "name" : "Category 4",
            "slug" : "category-4",
          },
          {
            "categoryId" : "aaaafffe",
            "name" : "Category 5",
            "slug" : "category-5",
          },
        ],

输出应该是这样的：

{
    {
        "categoryId": "aaaaffff",
        "name": "Category 1",
        "slug": "category-1",
        "count": 1
    },
    {
        "categoryId": "aaaafffd",
        "name": "Category 2",
        "slug": "category-2",
        "count": 2
    },
    {
        "categoryId": "aaaafffc",
        "name": "Category 3",
        "slug": "category-3",
        "count": 2
    },
    {
        "categoryId": "aaaafffb",
        "name": "Category 4",
        "slug": "category-4",
        "count": 1
    },
    {
        "categoryId": "aaaafffe",
        "name": "Category 5",
        "slug": "category-5",
        "count": 1
    }
}

是否有任何查询可以实现这一目标？先感谢您。也可以不更改映射吗？因为我无法更改映射（它来自管理）。

Answer 1

terms aggregation 应该是 keyword 类型的字段或任何其他适用于桶聚合的数据类型。要与text 一起使用，您需要启用fielddata。

了解更多请参考本官方documentation

使用索引映射和搜索查询添加工作示例

映射

"mappings" : {
  "dynamic" : "false",
  "properties" : {
    "categories" : {
      "type" : "nested",
      "properties" : {
        "categoryId" : {
          "type" : "text"
        },
        "name" : {
          "type" : "text"
        },
        "slug" : {
          "type" : "keyword"    <-- change data type to keyword
        }
      }
    }
  }
}

搜索查询

    {
    "aggs": {
        "count": {
            "nested": {
                "path": "categories"
            },
            "aggs": {
                "categories_count": {
                    "terms": {
                        "field": "categories.slug"
                    }
                }
            }
        }
    }
 }

搜索结果：

    "aggregations": {
    "count": {
      "doc_count": 7,
      "categories_count": {
        "doc_count_error_upper_bound": 0,
        "sum_other_doc_count": 0,
        "buckets": [
          {
            "key": "category-2",
            "doc_count": 2
          },
          {
            "key": "category-3",
            "doc_count": 2
          },
          {
            "key": "category-1",
            "doc_count": 1
          },
          {
            "key": "category-4",
            "doc_count": 1
          },
          {
            "key": "category-5",
            "doc_count": 1
          }
        ]
      }
    }
  }