如何在elasticsearch的嵌套聚合中存储空字段和非空字段？

Question

我在 elasticsearch 中有以下一组嵌套子聚合（field2 是 field1 的子聚合，field3 是 field2 的子聚合）。然而事实证明，field3 的术语聚合不会存储没有 field3 的文档。

我的理解是，除了 field3 的术语查询之外，我还必须使用 Missing subaggregation 查询来存储那些。

但我不确定如何将它添加到下面的查询中以同时存储两者。

{
  "size": 0,
  "aggregations": {
    "f1": {
      "terms": {
        "field": "field1",
        "size": 0,
        "order": {
          "_count": "asc"
        },
        "include": [
          "123"
        ]
      },
      "aggregations": {
        "field2": {
          "terms": {
            "field": "f2",
            "size": 0,
            "order": {
              "_count": "asc"
            },
            "include": [
              "tr"
            ]
          },
          "aggregations": {
            "field3": {
              "terms": {
                "field": "f3",
                "order": {
                  "_count": "asc"
                },
                "size": 0
              },
              "aggregations": {
                "aggTopHits": {
                  "top_hits": {
                    "size": 1
                  }
                }
              }
            }
          }
        }
      }
    }
  }
}

Answer 1

在 2.1.2 及更高版本中，您可以使用 missing parameter of the terms aggregation, which allows you to specify a default value for documents that are missing that field. (FYI, the missing parameter was available starting 2.0, but there was a bug 来阻止它处理子聚合，这就是您在这里使用它的方式。）

     ...
     "aggregations": {
        "field3": {
          "terms": {
            "field": "f3",
            "order": {
              "_count": "asc"
            },
            "size": 0,
            "missing": "n/a"     <----- provide a default here
          },
          "aggregations": {
            "aggTopHits": {
              "top_hits": {
                "size": 1
              }
            }
          }
        }
      }

但是，如果您使用的是 2.x 之前的 ES 集群，您可以使用 missing aggregation 与 field3 聚合相同的深度来存储文档像这样缺少 "f3"：

     ...
     "aggregations": {
        "field3": {
          "terms": {
            "field": "f3",
            "order": {
              "_count": "asc"
            },
            "size": 0
          },
          "aggregations": {
            "aggTopHits": {
              "top_hits": {
                "size": 1
              }
            }
          }
        },
        "missing_field3": {
          "missing" : {
            "field": "f3"
          },
          "aggregations": {
            "aggTopMissingHit": {
              "top_hits": {
                "size": 1
              }
            }
          }
        }
      }

如何在elasticsearch的嵌套聚合中存储空字段和非空字段？

how to bucket empty and non empty fields in nested aggregation in elasticsearch?

elasticsearch

elasticsearch-aggregation