ElasticSearch获取最后n条不同记录

Question

我正在尝试对存储在elasticsearch中的记录实现搜索查询。记录结构看起来像这样。

   {
    "_index" : "box_info_store",
    "_type" : "boxes",
    "_id" : "pWjQLWkBIJk0ORjd0X2P",
    "_score" : null,    
    "_source" : {
      "transactionID" : "60ab66cf24c9924f562bf1a2b5d92305d0a6",
      "boxNumber" : "Box3",
      "createDate" : "2013-09-17T00:00:00",
      "itemNumber" : "Item1",
      "address" : "Sample Address"
    }
  }

一个框可以包含多个项目。例如，Box3可以有Item1、Item2和Item3。因此，在elasticsearch中，我将有3个不同的文档。同时，同一个框和同一个项目也可以存在，但地址不同。这些文档的transactionID可能相同，也可能不相同。

我的要求是获取最后n个最近的和不同的TransactionID，以及它们的记录。

我尝试以下查询来获取最后7个不同的transactionID

GET /box_info_store/boxes/_search?size=7
{
  "query": {
    "bool": {
       "must": [
         {"match":{"boxNumber":"Box3"}},
         {"match":{"itemNumber":"Item1"}}
         ]
    }
  },
  "sort": [
    {
      "createDate": {
        "order": "desc"
      }
    }
  ],
  "aggs": {
    "distinct_transactions": {
      "terms": { "field": "transactionID"}
    }
  }
}

这让我找到了最后7个文档，其中boxNumber是Box3，itemNumber是Item1，但不是7个不同的transactionID，这7个文档中有两个具有相同的transactionID（但都有单独的地址）。但我的要求是获得7个不同的TransactionID，无论它返回多少个文档。

希望我能解释我自己。感谢您的帮助

谢啦

------编辑@gaurav9620，我运行第一个查询，得到的计数为32，然后我运行第二个查询，不同的计数为3，得到以下结果

{
  "took" : 1,
  "timed_out" : false,
  "_shards" : {
    "total" : 5,
    "successful" : 5,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : 32,
    "max_score" : null,
    "hits" : [
      {
        "_index" : "box_info_store",
        "_type" : "boxes",
        "_id" : "RWjRLWkBIJk0ORjdEX-L",
        "_score" : null,
        "_source" : {
          "transactionID" : "3087e106244f6247a5290fb21ce64254529c",
          "boxNumber" : "Box3",
          "createDate" : "2017-11-15T00:00:00",
          "itemNumber" : "Item1",
          "address" : "sampleAddress12",
        },
        "sort" : [
          1510704000000
        ]
      },
      {
        "_index" : "box_info_store",
        "_type" : "boxes",
        "_id" : "MGjQLWkBIJk0ORjdwX0M",
        "_score" : null,
        "_source" : {
          "transactionID" : "60ab66cf24c9924f562bf1a2b5d92305d0a6",
          "boxNumber" : "Box3",
          "createDate" : "2016-04-03T00:00:00",
          "itemNumber" : "Item1",
          "address" : "sampleAddress321",
        },
        "sort" : [
          1459641600000
        ]
      },
      ..........
      ..........
      ..........
      {
        "_index" : "box_info_store",
        "_type" : "boxes",
        "_id" : "AGjRLWkBIJk0ORjdK4CJ",
        "_score" : null,
        "_source" : {
          "transactionID" : "3087e106244f6247a5290fb21ce64254529c",
          "boxNumber" : "Box3",
          "createDate" : "1996-02-16T00:00:00",
          "itemNumber" : "Item1",
          "address" : "sampleAddress4324",
        },
        "sort" : [
          824428800000
        ]
      }
    ]
  },
  "aggregations" : {
    "unique_transactions" : {
      "doc_count_error_upper_bound" : 0,
      "sum_other_doc_count" : 16,
      "buckets" : [
        {
          "key" : "3087e106244f6247a5290fb21ce64254529c",
          "doc_count" : 6
        },
        {
          "key" : "27c5f3422f4482495d29e7b2c15c0e311743",
          "doc_count" : 5
        },
        {
          "key" : "c40e53212e74e24bf02a5bd2b134cf92bffb",
          "doc_count" : 5
        }
      ]
    }
  }
}

Answer 1

您使用的大小：表示检索到的原始文档的数量。

如果您的案例需要做的是：

>

GET /box_info_store/boxes/_search？ size=7{"查询"：{"bool"：{"必须": [ { "匹配"：{"boxNumber"："Box3" } }, { "匹配"：{"itemNumber"："Item1" } } ] } }, "排序": [ { "createDate"：{"order"："desc" } } ], "aggs"：{"distinct_transactions"：{"条款"：{"field"："transactionID"，"size"： 7 } } } }

编辑-------------------------------------

首先触发此查询

GET /box_info_store/boxes/_search?size=0
{
  "query": {
    "bool": {
      "must": [
        {
          "match": {
            "boxNumber": "Box3"
          }
        },
        {
          "match": {
            "itemNumber": "Item1"
          }
        }
      ]
    }
  }
}

在这里，您将找到与您的查询匹配的文档总数，您可以将其设置为n在此触发您的查询后，如下所示

GET /box_info_store/boxes/_search?size=**n**
{
  "query": {
    "bool": {
      "must": [
        {
          "match": {
            "boxNumber": "Box3"
          }
        },
        {
          "match": {
            "itemNumber": "Item1"
          }
        }
      ]
    }
  },
  "sort": [
    {
      "createDate": {
        "order": "desc"
      }
    }
  ],
  "aggs": {
    "distinct_transactions": {
      "terms": {
        "field": "transactionID",
        "size": NUMBER_OF_UNIQUE_TRANSACTION_IDS_TO_BE_FETCHED
      }
    }
  }
}