Elasticsearch必知必会的干货知识一：ES索引文档的CRUD

​ 若在传统DBMS 关系型数据库中查询海量数据，特别是模糊查询，一般我们都是使用like %查询的值%，但这样会导致无法应用索引，从而形成全表扫描效率低下，即使是在有索引的字段精确值查找，面对海量数据，效率也是相对较低的，所以目前一般的互联网公司或大型公司，若要查询海量数据，最好的办法就是使用搜索引擎，目前比较主流的搜索引擎框架就是：Elasticsearch，故今天我这里总结了Elasticsearch必知必会的干货知识一：ES索引文档的CRUD，后面陆续还会有其它干货知识分享，敬请期待。

1. ES索引文档的CRUD（6.X与7.X有区别，6.X中支持一个index创建多个type，而7.X中及以上只支持1个固定的type，即：_doc，API用法上也稍有不同）：

   1. Create创建索引文档【POST index/type/id可选，如果index、type、id已存在则重建索引文档（先删除后创建索引文档，与Put index/type/id 原理相同），如果在指定id情况下需要限制自动更新，则可以使用：index/type/id?op_type=create 或 index/type/id/_create，指明操作类型为创建，这样当存在的记录的情况下会报错】

      POST demo_users/_doc 或 demo_users/_doc/2vJKsm8BriJODA6s9GbQ/_create

      Request Body:

      {
      "userId":1,
      "username":"张三",
      "role":"administrator",
      "enabled":true,
      "createdDate":"2020-01-01T12:00:00"
      }
      

      Response Body:

      {
      "_index": "demo_users",
      "_type": "_doc",
      "_id": "2vJKsm8BriJODA6s9GbQ",
      "_version": 1,
      "result": "created",
      "_shards": {
      "total": 2,
      "successful": 1,
      "failed": 0
      },
      "_seq_no": 0,
      "_primary_term": 1
      }
      

   2. Get获取索引文档【Get index/type/id】

      Get demo_users/_doc/123

      Response Body:

      {
      "_index": "demo_users",
      "_type": "_doc",
      "_id": "123",
      "_version": 1,
      "found": true,
      "_source": {
      "userId": 1,
      "username": "张三",
      "role": "administrator",
      "enabled": true,
      "createdDate": "2020-01-01T12:00:00"
      }
      }
      

   3. Index Put重建索引文档【PUT index/type/id 或 index/type/id?op_type=index，id必传，如果id不存在文档则创建文档，否则先删除原有id文档后再重新创建文档，version加1】

      Put/POST demo_users/_doc/123 或 demo_users/_doc/123?op_type=index

      Request Body:

      {
      "userId":1,
      "username":"张三",
      "role":"administrator",
      "enabled":true,
      "createdDate":"2020-01-01T12:00:00",
      "remark":"仅演示"
      }
      

      Response Body:

      {
      "_index": "demo_users",
      "_type": "_doc",
      "_id": "123",
      "_version": 4,
      "result": "updated",
      "_shards": {
      "total": 2,
      "successful": 2,
      "failed": 0
      },
      "_seq_no": 10,
      "_primary_term": 1
      }
      

   4. Update更新索引文档【POST index/type/id/_update 请求体必需是{"doc":{具体的文档JSON}},如果指定的键字段已存在则更新，如果指定的键字段不存在则附加新的键值对，支持多层级嵌套，多次请求，如果有字段值有更新则version加1，否则提示更新0条 】

      POST demo_users/_doc/123/_update

      Request Body:

      {
        "doc": {
          "userId": 1,
          "username": "张三",
          "role": "administrator",
          "enabled": true,
          "createdDate": "2020-01-01T12:00:00",
          "remark": "仅演示POST更新5",
          "updatedDate": "2020-01-17T15:30:00"
        }
      }
      

      Response Body:

      {
      "_index": "demo_users",
      "_type": "_doc",
      "_id": "123",
      "_version": 26,
      "result": "updated",
      "_shards": {
      "total": 2,
      "successful": 2,
      "failed": 0
      },
      "_seq_no": 35,
      "_primary_term": 1
      }
      

   5. Delete删除索引文档【DELETE index/type/id】

      DELETE demo_users/_doc/123

      Response Body:

      {
      "_index": "demo_users",
      "_type": "_doc",
      "_id": "123",
      "_version": 2,
      "result": "deleted",
      "_shards": {
      "total": 2,
      "successful": 2,
      "failed": 0
      },
      "_seq_no": 39,
      "_primary_term": 1
      }
      

   6. Bulk批量操作文档【POST _bulk 或 index/_bulk 或 index/type/_bulk 一次请求支持进行多个索引、多个type的多种不同的CRUD操作，如果操作中有某个出现错误不会影响其它操作；】

      POST _bulk

      Request Body:(注意最后还得多一个换行，因为ES是根据换行符来识别多条命令的，如果缺少最后一条换行则会报错，注意请求体非标准的JSON，每行才是一个JSON，整体顶多可看成是\n区分的JSON对象数组)

      { "index" : { "_index" : "demo_users_test", "_type" : "_doc", "_id" : "1" } }
      { "bulk_field1" : "测试创建index" }
      { "delete" : { "_index" : "demo_users", "_type" : "_doc", "_id" : "123" } }
      { "create" : { "_index" : "demo_users", "_type" : "_doc", "_id" : "2" } }
      { "bulk_field2" : "测试创建index2" }
      { "update" : { "_index" : "demo_users_test","_type" : "_doc","_id" : "1" } }
      { "doc": {"bulk_field1" : "测试创建index1","bulk_field2" : "测试创建index2"} }
      
      

      Response Body:

      {
          "took": 162,
          "errors": true,
          "items": [
              {
                  "index": {
                      "_index": "demo_users_test",
                      "_type": "_doc",
                      "_id": "1",
                      "_version": 8,
                      "result": "updated",
                      "_shards": {
                          "total": 2,
                          "successful": 2,
                          "failed": 0
                      },
                      "_seq_no": 7,
                      "_primary_term": 1,
                      "status": 200
                  }
              },
              {
                  "delete": {
                      "_index": "demo_users",
                      "_type": "_doc",
                      "_id": "123",
                      "_version": 2,
                      "result": "not_found",
                      "_shards": {
                          "total": 2,
                          "successful": 2,
                          "failed": 0
                      },
                      "_seq_no": 44,
                      "_primary_term": 1,
                      "status": 404
                  }
              },
              {
                  "create": {
                      "_index": "demo_users",
                      "_type": "_doc",
                      "_id": "2",
                      "status": 409,
                      "error": {
                          "type": "version_conflict_engine_exception",
                          "reason": "[_doc][2]: version conflict, document already exists (current version [1])",
                          "index_uuid": "u7WE286CQnGqhHeuwW7oyw",
                          "shard": "2",
                          "index": "demo_users"
                      }
                  }
              },
              {
                  "update": {
                      "_index": "demo_users_test",
                      "_type": "_doc",
                      "_id": "1",
                      "_version": 9,
                      "result": "updated",
                      "_shards": {
                          "total": 2,
                          "successful": 2,
                          "failed": 0
                      },
                      "_seq_no": 8,
                      "_primary_term": 1,
                      "status": 200
                  }
              }
          ]
      }
      

   7. mGet【POST _mget 或 index/_mget 或 index/type/_mget ，如果指定了index或type，则请求报文中则无需再指明index或type，可以通过_source指明要查询的include以及要排除exclude的字段】

      POST _mget

      Request Body:

      {
        "docs": [
          {
            "_index": "demo_users",
            "_type": "_doc",
            "_id": "12345"
          },
          {
            "_index": "demo_users",
            "_type": "_doc",
            "_id": "1234567",
            "_source": [
              "userId",
              "username",
              "role"
            ]
          },
          {
            "_index": "demo_users",
            "_type": "_doc",
            "_id": "1234",
            "_source": {
              "include": [
                "userId",
                "username"
              ],
              "exclude": [
                "role"
              ]
            }
          }
        ]
      }
      

      Response Body:

      {
          "docs":[
              {
                  "_index":"demo_users",
                  "_type":"_doc",
                  "_id":"12345",
                  "_version":1,
                  "found":true,
                  "_source":{
                      "userId":1,
                      "username":"张三",
                      "role":"administrator",
                      "enabled":true,
                      "createdDate":"2020-01-01T12:00:00"
                  }
              },
              {
                  "_index":"demo_users",
                  "_type":"_doc",
                  "_id":"1234567",
                  "_version":7,
                  "found":true,
                  "_source":{
                      "role":"administrator",
                      "userId":1,
                      "username":"张三"
                  }
              },
              {
                  "_index":"demo_users",
                  "_type":"_doc",
                  "_id":"1234",
                  "_version":1,
                  "found":true,
                  "_source":{
                      "userId":1,
                      "username":"张三"
                  }
              }
          ]
      }
      

      POST demo_users/_doc/_mget

      Request Body:

      {
        "ids": [
          "1234",
          "12345",
          "123457"
        ]
      }
      

      Response Body:

      {
          "docs":[
              {
                  "_index":"demo_users",
                  "_type":"_doc",
                  "_id":"1234",
                  "_version":1,
                  "found":true,
                  "_source":{
                      "userId":1,
                      "username":"张三",
                      "role":"administrator",
                      "enabled":true,
                      "createdDate":"2020-01-01T12:00:00",
                      "remark":"仅演示"
                  }
              },
              {
                  "_index":"demo_users",
                  "_type":"_doc",
                  "_id":"12345",
                  "_version":1,
                  "found":true,
                  "_source":{
                      "userId":1,
                      "username":"张三",
                      "role":"administrator",
                      "enabled":true,
                      "createdDate":"2020-01-01T12:00:00"
                  }
              },
              {
                  "_index":"demo_users",
                  "_type":"_doc",
                  "_id":"123457",
                  "found":false
              }
          ]
      }
      

   8. _update_by_query根据查询条件更新匹配到的索引文档的指定字段【POST index/_update_by_query 请求体写查询条件以及更新的字段，更新字段这里采用了painless脚本进行灵活更新】

      POST demo_users/_update_by_query

      Request Body:（意思是查询role=administrator【可能大家看到keyword，这是因为role字段为text类型，无法直接匹配，需要借助于子字段role.keyword，如果有不理解后面会有简要说明】，更新role为poweruser、remark为remark+采用_update_by_query更新）

      {
          "script":{ "source":"ctx._source.role=params.role;ctx._source.remark=ctx._source.remark+params.remark",
              "lang":"painless",
              "params":{
                  "role":"poweruser",
                  "remark":"采用_update_by_query更新"
              }
          },
          "query":{
              "term":{
                  "role.keyword":"administrator"
              }
          }
      }
      

      painless写法请具体参考：painless语法教程

      Response Body:

      {
      "took": 114,
      "timed_out": false,
      "total": 6,
      "updated": 6,
      "deleted": 0,
      "batches": 1,
      "version_conflicts": 0,
      "noops": 0,
      "retries": {
      "bulk": 0,
      "search": 0
      },
      "throttled_millis": 0,
      "requests_per_second": -1,
      "throttled_until_millis": 0,
      "failures": [ ]
      }
      

   9. _delete_by_query根据查询条件删除匹配到的索引文档【 POST index/_delete_by_query 请求体写查询匹配条件】

      POST demo_users/_delete_by_query

      Request Body:（意思是查询enabled=false）

      {
        "query": {
          "match": {
            "enabled": false
          }
        }
      }
      

      Response Body:

         {
                 "took":29,
                 "timed_out":false,
                 "total":3,
                 "deleted":3,
                 "batches":1,
                 "version_conflicts":0,
                 "noops":0,
                 "retries":{
                     "bulk":0,
                     "search":0
                 },
                 "throttled_millis":0,
                 "requests_per_second":-1,
                 "throttled_until_millis":0,
                 "failures":[
      
                 ]
            }
      

   10. search查询

       1. URL GET查询（GET index/_search?q=query_string语法，注意中文内容默认分词器是一个汉字拆分成一个term）

          
          A.Term Query:【即分词片段(词条)查询，注意这里讲的包含是指与分词片段匹配】
          GET /demo_users/_search?q=role:poweruser //指定字段查询,即：字段包含查询的值
          
          GET /demo_users/_search?q=poweruser //泛查询(没有指定查询的字段)，即查询文档中所有字段包含poweruser的值，只要有一个字段符合，那么该文档将会被返回
          
          B.Phrase Query【即分组查询】
          操作符有：AND / OR  / NOT 或者表示为： && / || / !
          +表示must -表示must_not 例如：field:(+a -b)意为field中必需包含a但不能包含b
          
          GET /demo_users/_search?q=remark:(POST test)
          GET /demo_users/_search?q=remark:(POST OR test)
          GET /demo_users/_search?q=remark:"POST test"
          //分组查询，即：查询remark中包含POST 或 test的文档记录
          
          GET /demo_users/_search?q=remark:(test AND POST) //remark同时包含test与POST
          GET /demo_users/_search?q=remark:(test NOT POST) //remark包含test但不包含POST
          
          C.范围查询
          区间表示：[]闭区间，{}开区间
          如：year:[2019 TO 2020] 或 {2019 TO 2020} 或 {2019 TO 2020] 或 [* TO 2020]
          算数符号
          year:>2019 或 (>2012 && <=2020) 或 (+>=2012 +<=2020)
          
          GET /demo_users/_search?q=userId:>123 //查询userId字段大于123的文档记录
          
          D.通配符查询
          ?表示匹配任意1个字符，*表示匹配0或多个字符 例如：role:power* , role:use?
          
          GET /demo_users/_search?q=role:power* //查询role字段前面是power，后面可以是0或多个其它任意字符。
          
          可使用正则表达式，如：username:张三\d+
          
          可使用近似查询偏移量（slop）提高查询匹配结果【使用~N，N表示偏移量】
          GET /demo_users/_search?q=remark:tett~1 //查询remark中包含test的文档，但实际写成了tett，故使用~1偏移近似查询，可以获得test的查询结果
          
          GET /demo_users/_search?q=remark:"i like shenzhen"~2 //查询i like shenzhen但实际remark字段中值为：i like hubei and shenzhen，比查询值多了 hubei and，这里使用~2指定可偏移相隔2个term（这里即两个单词），最终也是可以查询出结果
          
          

       2. DSL POST查询（POST index/_search）

          POST demo_users/_search

          Request Body:

          {
              "query":{
                  "bool":{
                      "must":[
                          {
                              "term":{
                                  "enabled":"true"  #查询enabled=true
                              }
                          },
                          {
                              "term":{
                                  "role.keyword":"poweruser" #且role=poweruser
                              }
                          },
                          {
                              "query_string":{
                                  "default_field":"username.keyword",
                                  "query":"张三" #且 username 包含张三
                              }
                          }
                      ],
                      "must_not":[
          
                      ],
                      "should":[
          
                      ]
                  }
              },
              "from":0,
              "size":1000,
              "sort":[
                  {
                      "createdDate":"desc"  #根据createdDate倒序
                  }
              ],
              "_source":{ #指明返回的字段，includes需返回字段，excludes不需要返回字段
                  "includes":[
                      "role",
                      "username",
                      "userId",
                      "remark"
                  ],
                  "excludes":[
          
                  ]
              }
          }
          
          

具体用法可参见：

【Elasticsearch】query_string的各种用法

Elasticsearch中 match、match_phrase、query_string和term的区别

Elasticsearch Query DSL 整理总结

[布尔查询Bool Query]

最后附上ES官方的API操作链接指引：

Indices APIs：负责索引Index的创建（create）、删除（delete）、获取（get）、索引存在（exist）等操作。

Document APIs：负责索引文档的创建（index）、删除（delete）、获取（get）等操作。

Search APIs：负责索引文档的search（查询），Document APIS根据doc_id进行查询，Search APIs]根据条件查询。

Aggregations：负责针对索引的文档各维度的聚合（Aggregation）。

cat APIs：负责查询索引相关的各类信息查询。

Cluster APIs：负责集群相关的各类信息查询。