Elasticsearch--简单集群管理操作、简单索引操作及文档增删改查

忘是亡心i 2021-08-26 15:34 307阅读 0赞

### 简单集群管理操作 ###

es提供了一套api，叫做cat api，可以查看es中各种各样的数据。

**查看集群状态：**

GET /_cat/health?v

![在这里插入图片描述][20200309210149210.png]

集群的状态用3中颜色表示：

*  green：个索引的primary shard和replica shard都是active状态的
 *  yellow：每个索引的primary shard都是active状态的，但是部分replica shard不是active状态，处于不可用的状态
 *  red：不是所有索引的primary shard都是active状态的，部分索引有数据丢失了

为什么现在会处于一个yellow状态？

我们现在就一个笔记本电脑，就启动了一个es进程，相当于就只有一个node。现在es中有一个index，就是kibana自己内置建立的index。由于默认的配置是给每个index分配5个primary shard和5个replica shard，而且primary shard和replica shard不能在同一台机器上（为了容错）。现在kibana自己建立的index是1个primary shard和1个replica shard。当前就一个node，所以只有1个primary shard被分配了和启动了，但是一个replica shard没有第二台机器去启动。

做一个小实验：此时只要启动第二个es进程，就会在es集群中有2个node，然后那1个replica shard就会自动分配过去，然后cluster status就会变成green状态。

**查看索引：**

GET /_cat/indices?v

![在这里插入图片描述][20200309210423174.png]

### 简单索引操作 ###

**新增索引：**

PUT /test_index?pretty

![在这里插入图片描述][20200309211053447.png]  
**删除索引：**

DELETE /test_index?pretty

![20200309211139189.png][]

### 增删改查 ###

**新增:**

//格式
    PUT /index/type/id
    {
      "json数据"
    }

示例：

PUT /ecommerce/product/1
    { 
        "name" : "gaolujie yagao",
        "desc" :  "gaoxiao meibai",
        "price" :  30,
        "producer" :      "gaolujie producer",
        "tags": [ "meibai", "fangzhu" ]
    }
    
    PUT /ecommerce/product/2
    { 
        "name" : "jiajieshi yagao",
        "desc" :  "youxiao fangzhu",
        "price" :  25,
        "producer" :      "jiajieshi producer",
        "tags": [ "fangzhu" ]
    }
    
    PUT /ecommerce/product/3
    { 
        "name" : "zhonghua yagao",
        "desc" :  "caoben zhiwu",
        "price" :  40,
        "producer" :      "zhonghua producer",
        "tags": [ "qingxin" ]
    }

返回值：

{ 
      "_index": "ecommerce",
      "_type": "product",
      "_id": "1",
      "_version": 1,
      "result": "created",
      "_shards": { 
        "total": 2,//主分片一个，副本分片一个，每条数据应该存2份
        "successful": 1,//但是我们只有一个节点，只有主分片存入成功
        "failed": 0
      },
      "created": true
    }

es会自动建立index和type，不需要提前创建，而且es默认会对document每个field都建立倒排索引，让其可以被搜索

**查询：**

//语法格式：
    GET /index/type/id

示例：

GET /ecommerce/product/1

{ 
      "_index": "ecommerce",
      "_type": "product",
      "_id": "1",
      "_version": 1,
      "found": true,
      "_source": { 
        "name": "gaolujie yagao",
        "desc": "gaoxiao meibai",
        "price": 30,
        "producer": "gaolujie producer",
        "tags": [
          "meibai",
          "fangzhu"
        ]
      }
    }

**修改：**

*  方式一：替换

PUT /ecommerce/product/1
    { 
        "name" : "jiaqiangban gaolujie yagao",
        "desc" :  "gaoxiao meibai",
        "price" :  30,
        "producer" :      "gaolujie producer",
        "tags": [ "meibai", "fangzhu" ]
    }

{ 
      "_index": "ecommerce",
      "_type": "product",
      "_id": "1",
      "_version": 2,//更新为2
      "result": "updated",
      "_shards": { 
        "total": 2,
        "successful": 1,
        "failed": 0
      },
      "created": false
    }

替换方式有一个不好，即使必须带上所有的field，才能去进行信息的修改；否则会造成数据丢失

*  方式二：更新（加上\_update）

POST /ecommerce/product/1/_update
    { 
      "doc": { 
        "name": "jjj gaolujie yagao"
      }
    }

{ 
      "_index": "ecommerce",
      "_type": "product",
      "_id": "1",
      "_version": 3,
      "result": "updated",
      "_shards": { 
        "total": 2,
        "successful": 1,
        "failed": 0
      }
    }

**删除**

格式：
    DELETE /index/type/id

示例：

DELETE /ecommerce/product/1

{ 
      "found": true,
      "_index": "ecommerce",
      "_type": "product",
      "_id": "1",
      "_version": 4,
      "result": "deleted",
      "_shards": { 
        "total": 2,
        "successful": 1,
        "failed": 0
      }
    }

再次查询：

{ 
      "_index": "ecommerce",
      "_type": "product",
      "_id": "1",
      "found": false
    }

[20200309210149210.png]: /images/20210813/d887e9e8ff8446da9d6faf9d9a423405.png
[20200309210423174.png]: /images/20210813/2fbd10f432cd42cca2ed898ed67d0440.png
[20200309211053447.png]: /images/20210813/6c69331710b64d4aaeee27e4058df6fc.png
[20200309211139189.png]: /images/20210813/ce29faa1a7594c479e7517326f8e7d2f.png