Elasticsearch由浅入深（六）批量操作：mget批量查询、bulk批量增删改、路由原理、增删改内部原理、document查询内部原理、bulk api的奇特json格式

mget批量查询

1. 批量查询的好处
   就是一条一条的查询，比如说要查询100条数据，那么就要发送100次网络请求，这个开销还是很大的
   如果进行批量查询的话，查询100条数据，就只要发送1次网络请求，网络请求的性能开销缩减100倍
2. mget批量查询的语法
   

   GET _mget
   {
     "docs":[
       {
         "_index":"test_index",
         "_type":"test_type",
         "_id":1
       },
       {
         "_index":"test_index",
         "_type":"test_type",
         "_id":2
       }
       ]
   }

   {
     "took": 2,
     "timed_out": false,
     "_shards": {
       "total": 5,
       "successful": 5,
       "failed": 0
     },
     "hits": {
       "total": 9,
       "max_score": 1,
       "hits": [
         {
           "_index": "test_index",
           "_type": "test_type",
           "_id": "AWypxxLYFCl_S-ox4wvd",
           "_score": 1,
           "_source": {
             "test_content": "my test"
           }
         },
         {
           "_index": "test_index",
           "_type": "test_type",
           "_id": "8",
           "_score": 1,
           "_source": {
             "test_field": "test client 2"
           }
         },
         {
           "_index": "test_index",
           "_type": "test_type",
           "_id": "10",
           "_score": 1,
           "_source": {
             "test_field1": "test1",
             "test_field2": "updated test2"
           }
         },
         {
           "_index": "test_index",
           "_type": "test_type",
           "_id": "2",
           "_score": 1,
           "_source": {
             "test_content": "my test"
           }
         },
         {
           "_index": "test_index",
           "_type": "test_type",
           "_id": "4",
           "_score": 1,
           "_source": {
             "test_field": "test test"
           }
         },
         {
           "_index": "test_index",
           "_type": "test_type",
           "_id": "6",
           "_score": 1,
           "_source": {
             "test_field": "test test"
           }
         },
         {
           "_index": "test_index",
           "_type": "test_type",
           "_id": "1",
           "_score": 1,
           "_source": {
             "test_field1": "test field1",
             "test_field2": "test field2"
           }
         },
         {
           "_index": "test_index",
           "_type": "test_type",
           "_id": "7",
           "_score": 1,
           "_source": {
             "test_field": "test client 1"
           }
         },
         {
           "_index": "test_index",
           "_type": "test_type",
           "_id": "11",
           "_score": 1,
           "_source": {
             "num": 0,
             "tags": []
           }
         }
       ]
     }
   }

   View Code