ElasticSearch-query-multi-get批处理
2025-01-22 08:19:30    829 字    #elasticSearch
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ElasticSearch版本：6.5.0(点击跳转官方文档)

ElasticSearch multi-get/mget 检索多个文档/批处理

在Elasticsearch中，检索多个文档虽然很快，但合并多个请求可以减轻网络开销。可以使用 multi-get 或者 mget。

下面示例模拟，从三个索引中查找文档。

如果想指定返回字段，增加一个_source参数

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GET /_mget
{
  "docs":[
    {
      "_index":"demo",
      "_type":"testDate",
      "_id":"1"
    },{
      "_index": "megacorp",
      "_type": "employee",
      "_id": "5"
    },{
      "_index": "books",
      "_type": "book",
      "_id": "19",
      "_source":"publish"
    }
    ]
}

响应报文

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{
  "docs": [
    {
      "_index": "demo",
      "_type": "testDate",
      "_id": "1",
      "_version": 2,
      "found": true,
      "_source": {
        "name": "cyx111",
        "age": "11",
        "address": "nanjing11"
      }
    },
    {
      "_index": "megacorp",
      "_type": "employee",
      "_id": "5",
      "_version": 1,
      "found": true,
      "_source": {
        "about": "i love evertything",
        "last_name": "yixin",
        "interests": [
          "read book",
          "swim"
        ],
        "first_name": "cheng",
        "age": "22"
      }
    },
    {
      "_index": "books",
      "_type": "book",
      "_id": "19",
      "_version": 2,
      "found": true,
      "_source": {
        "publish": "高等教育出版社"
      }
    }
  ]
}

如果想检索的多个文档，都在一个_index中（甚至在一个_type中），url中就可以指定_index、_type

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GET /demo/testDate/_mget
{
  "docs":[
    {
      "_id":"2"
    },{
      "_id":"3"
    }
    ]
}

响应报文

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{
  "docs": [
    {
      "_index": "demo",
      "_type": "testDate",
      "_id": "2",
      "_version": 2,
      "found": true,
      "_source": {
        "name": "cyx2",
        "age": "23",
        "address": "nanjing2",
        "price": "100.00",
        "tags": [
          "test",
          "test2",
          "test3"
        ]
      }
    },
    {
      "_index": "demo",
      "_type": "testDate",
      "_id": "3",
      "_version": 1,
      "found": true,
      "_source": {
        "name": "cyx333",
        "age": "333",
        "address": "nanjing333"
      }
    }
  ]
}

如果，多个文档都是同一个索引、类型下，可以换这种写法：

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GET /demo/testDate/_mget
{
  "ids":["1","2"]
}

响应报文

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{
  "docs": [
    {
      "_index": "demo",
      "_type": "testDate",
      "_id": "1",
      "_version": 2,
      "found": true,
      "_source": {
        "name": "cyx111",
        "age": "11",
        "address": "nanjing11"
      }
    },
    {
      "_index": "demo",
      "_type": "testDate",
      "_id": "2",
      "_version": 2,
      "found": true,
      "_source": {
        "name": "cyx2",
        "age": "23",
        "address": "nanjing2",
        "price": "100.00",
        "tags": [
          "test",
          "test2",
          "test3"
        ]
      }
    }
  ]
}

如果，其中某个文档不存在，返回的结果如下：

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{
  "docs": [
    {
      "_index": "demo",
      "_type": "testDate",
      "_id": "1",
      "_version": 2,
      "found": true,
      "_source": {
        "name": "cyx111",
        "age": "11",
        "address": "nanjing11"
      }
    },
    {
      "_index": "demo",
      "_type": "testDate",
      "_id": "pppp",
      "found": false
    }
  ]
}

不存在的文档，并不影响第一个文档的检索，每个文档的检索都是独立的。