top hits的bucket路径应该是什么

Question

我正在尝试在 elasticsearch 中创建一个查询，它能够检索每个组的文档，这是每个组中的最新文档并满足特定条件。但是我没能解决这个问题。

假设以下文档在 elasticsearch 的 myindex 中被索引：

POST /myindex/_bulk
{ "index":{} }
{ "objid": 1, "ident":"group1","version":1, "chdate": 1, "field1" : 1}
{ "index":{} }
{ "objid": 2, "ident":"group1","version":2, "chdate": 2, "field1" : 0}
{ "index":{} }
{ "objid": 3, "ident":"group1","version":2, "chdate": 3, "field1" : 1}
{ "index":{} }
{ "objid": 4, "ident":"group1","version":2, "chdate": 4, "field1" : 0}
{ "index":{} }
{ "objid": 5, "ident":"group1","version":3, "chdate": 1, "field1" : 0}

我想找到所有文档，如果文档的 chdate 最高，则将 field1 设置为 x，对于每个标识和版本，将 field1 设置为 x。

在 x 为 0 的情况下，应返回具有 objid 4 和 5 的文档在 x 为 1 的情况下，应返回具有 objid 1 的文档

ChatGpt 建议这个查询：

{
  "size": 0,
  "aggs": {
    "ident": {
      "terms": {
        "field": "ident"
      },
      "aggs": {
        "version": {
          "terms": {
            "field": "version"
          },
          "aggs": {
            "top_hits_agg": {
              "top_hits": {
                "size": 1,
                "sort": [
                  {
                    "chdate": {
                      "order": "desc"
                    }
                  }
                ]
              }
            },
            "field1_filter": {
              "bucket_selector": {
                "buckets_path": {
                  "hits": "top_hits_agg.hits.hits",
                  "field1": "top_hits_agg.hits.hits._source.field1"
                },
                "script": {
                  "source": "params.field1 == 0"
                }
              }
            }
          }
        }
      }
    }
  }
}

但是 elasticsearch 出现以下错误

{
  "error" : {
    "root_cause" : [
      {
        "type" : "action_request_validation_exception",
        "reason" : "Validation Failed: 1: No aggregation found for path [top_hits_agg.hits.hits._source.field1];"
      }
    ],
    "type" : "action_request_validation_exception",
    "reason" : "Validation Failed: 1: No aggregation found for path [top_hits_agg.hits.hits._source.field1];"
  },
  "status" : 400
}

任何知道在这种情况下桶路径应该是什么的人

提前致谢

Answer 1

您可以结合使用 multi-terms 和 top hits 聚合来达到您需要的结果。

Multi Terms 聚合，将创建基于

version

和

ident

的独特桶。然后 top-hits bucket 将检索具有最高

chdate

的文档（基于创建的 buckets）

搜索查询：

{
  "size": 0,
  "query": {
    "term": {
      "field1": 0
    }
  },
  "aggs": {
    "genres_and_products": {
      "multi_terms": {
        "terms": [
          {
            "field": "version"
          },
          {
            "field": "ident.keyword"
          }
        ]
      },
      "aggs": {
        "topHits": {
          "top_hits": {
            "sort": [
              {
                "chdate": {
                  "order": "desc"
                }
              }
            ],
            "size": 1,
            "_source": {
              "includes": "objid"
            }
          }
        }
      }
    }
  }
}

搜索结果：

{
  "took": 15,
  "timed_out": false,
  "_shards": {
    "total": 1,
    "successful": 1,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": {
      "value": 3,
      "relation": "eq"
    },
    "max_score": null,
    "hits": []
  },
  "aggregations": {
    "genres_and_products": {
      "doc_count_error_upper_bound": 0,
      "sum_other_doc_count": 0,
      "buckets": [
        {
          "key": [
            2,
            "group1"
          ],
          "key_as_string": "2|group1",
          "doc_count": 2,
          "topHits": {
            "hits": {
              "total": {
                "value": 2,
                "relation": "eq"
              },
              "max_score": null,
              "hits": [
                {
                  "_index": "75889252",
                  "_id": "gtowPIcBFkuh8-KNVHAi",
                  "_score": null,
                  "_source": {
                    "objid": 4
                  },
                  "sort": [
                    4
                  ]
                }
              ]
            }
          }
        },
        {
          "key": [
            3,
            "group1"
          ],
          "key_as_string": "3|group1",
          "doc_count": 1,
          "topHits": {
            "hits": {
              "total": {
                "value": 1,
                "relation": "eq"
              },
              "max_score": null,
              "hits": [
                {
                  "_index": "75889252",
                  "_id": "g9owPIcBFkuh8-KNVHAi",
                  "_score": null,
                  "_source": {
                    "objid": 5
                  },
                  "sort": [
                    1
                  ]
                }
              ]
            }
          }
        }
      ]
    }
  }
}

如上图所示，您会注意到 top hits 聚合桶，为您提供所需的结果。