1、document數(shù)據(jù)格式

面向文檔的搜索分析引擎

（1）應(yīng)用系統(tǒng)的數(shù)據(jù)結(jié)構(gòu)都是面向?qū)ο蟮?，?fù)雜的
（2）對(duì)象數(shù)據(jù)存儲(chǔ)到數(shù)據(jù)庫(kù)中，只能拆解開(kāi)來(lái)，變?yōu)楸馄降亩鄰埍?，每次查詢的時(shí)候還得還原回對(duì)象格式，相當(dāng)麻煩
（3）ES是面向文檔的，文檔中存儲(chǔ)的數(shù)據(jù)結(jié)構(gòu)，與面向?qū)ο蟮臄?shù)據(jù)結(jié)構(gòu)是一樣的，基于這種文檔數(shù)據(jù)結(jié)構(gòu)，es可以提供復(fù)雜的索引，全文檢索，分析聚合等功能
（4）es的document用json數(shù)據(jù)格式來(lái)表達(dá)

public class Employee {

  private String email;
  private String firstName;
  private String lastName;
  private EmployeeInfo info;
  private Date joinDate;

}

private class EmployeeInfo {
  
  private String bio; // 性格
  private Integer age;
  private String[] interests; // 興趣愛(ài)好

}

EmployeeInfo info = new EmployeeInfo();
info.setBio("curious and modest");
info.setAge(30);
info.setInterests(new String[]{"bike", "climb"});

Employee employee = new Employee();
employee.setEmail("zhangsan@sina.com");
employee.setFirstName("san");
employee.setLastName("zhang");
employee.setInfo(info);
employee.setJoinDate(new Date());

employee對(duì)象：里面包含了Employee類自己的屬性，還有一個(gè)EmployeeInfo對(duì)象

數(shù)據(jù)庫(kù)的關(guān)系型數(shù)據(jù)格式

兩張表：employee表，employee_info表，將employee對(duì)象的數(shù)據(jù)重新拆開(kāi)來(lái)，變成Employee數(shù)據(jù)和EmployeeInfo數(shù)據(jù)
employee表：email，first_name，last_name，join_date，4個(gè)字段
employee_info表：bio，age，interests，3個(gè)字段；此外還有一個(gè)外鍵字段，比如employee_id，關(guān)聯(lián)著employee表

es的document數(shù)據(jù)格式

{
    "email":      "zhangsan@sina.com",
    "first_name": "san",
    "last_name": "zhang",
    "info": {
        "bio":         "curious and modest",
        "age":         30,
        "interests": [ "bike", "climb" ]
    },
    "join_date": "2017/01/01"
}

上面就是es的document數(shù)據(jù)格式和數(shù)據(jù)庫(kù)的關(guān)系型數(shù)據(jù)格式的區(qū)別

2、電商網(wǎng)站商品管理案例背景介紹

有一個(gè)電商網(wǎng)站，需要為其基于ES構(gòu)建一個(gè)后臺(tái)系統(tǒng)，提供以下功能：

（1）對(duì)商品信息進(jìn)行CRUD（增刪改查）操作
（2）執(zhí)行簡(jiǎn)單的結(jié)構(gòu)化查詢
（3）可以執(zhí)行簡(jiǎn)單的全文檢索，以及復(fù)雜的phrase（短語(yǔ)）檢索
（4）對(duì)于全文檢索的結(jié)果，可以進(jìn)行高亮顯示
（5）對(duì)數(shù)據(jù)進(jìn)行簡(jiǎn)單的聚合分析
（6）現(xiàn)在全部都是用es的restful api來(lái)實(shí)現(xiàn)es的所有知識(shí)點(diǎn)和功能點(diǎn)，后續(xù)會(huì)使用java api

3、簡(jiǎn)單的集群管理

（1）快速檢查集群的健康狀況，es提供了一套api，叫做cat api，可以查看es中各種各樣的數(shù)據(jù)

GET /_cat/health?v

epoch      timestamp cluster       status node.total node.data shards pri relo init unassign pending_tasks max_task_wait_time active_shards_percent
1522762745 21:39:05  elasticsearch yellow          1         1      1   1    0    0        1             0                  -                 50.0%

如何快速了解集群的健康狀況？green、yellow、red？

green：每個(gè)索引的primary shard和replica shard都是active狀態(tài)的
yellow：每個(gè)索引的primary shard都是active狀態(tài)的，但是部分replica shard不是active狀態(tài)，處于不可用的狀態(tài)
red：不是所有索引的primary shard都是active狀態(tài)的，部分索引有數(shù)據(jù)丟失了

為什么現(xiàn)在會(huì)處于一個(gè)yellow狀態(tài)？

我們現(xiàn)在就一個(gè)筆記本電腦，就啟動(dòng)了一個(gè)es進(jìn)程，相當(dāng)于就只有一個(gè)node。現(xiàn)在es中有一個(gè)index，就是kibana自己內(nèi)置建立的index。由于默認(rèn)的配置是給每個(gè)index分配5個(gè)primary shard和5個(gè)replica shard，而且primary shard和replica shard不能在同一臺(tái)機(jī)器上（為了容錯(cuò)）?，F(xiàn)在kibana自己建立的index是1個(gè)primary shard和1個(gè)replica shard。當(dāng)前就一個(gè)node，所以只有1個(gè)primary shard被分配了和啟動(dòng)了，但是一個(gè)replica shard沒(méi)有第二臺(tái)機(jī)器去啟動(dòng)。

做一個(gè)小實(shí)驗(yàn)：此時(shí)只要啟動(dòng)第二個(gè)es進(jìn)程，就會(huì)在es集群中有2個(gè)node，然后那1個(gè)replica shard就會(huì)自動(dòng)分配過(guò)去，然后cluster status就會(huì)變成green狀態(tài)。

epoch      timestamp cluster       status node.total node.data shards pri relo init unassign pending_tasks max_task_wait_time active_shards_percent
1522763492 21:51:32  elasticsearch green           2         2      2   1    0    0        0             0                  -                100.0%

（2） 快速查看集群中有哪些索引

GET /_cat/indices?v

health status index   uuid                   pri rep docs.count docs.deleted store.size pri.store.size
yellow open   .kibana sny6Sj_JS6CaYEV079oAQg   1   1          1            0      3.1kb          3.1kb

index：索引
pri：primary shard
rep：replica shard
docs.count：document數(shù)量
docs.deleted：document刪除數(shù)量
store.size：總數(shù)據(jù)占用大小
pri.store.size：primary shard存儲(chǔ)數(shù)據(jù)大小

（3） 簡(jiǎn)單的索引操作

創(chuàng)建索引：PUT /test_index?prett

health status index      uuid                   pri rep docs.count docs.deleted store.size pri.store.size
yellow open   .kibana    sny6Sj_JS6CaYEV079oAQg   1   1          1            0      3.1kb          3.1kb
yellow open   test_index xev5PyVMTwCNt_LxwqFZWA   5   1          0            0       650b           650b

刪除索引：DELETE /test_index?pretty

health status index   uuid                   pri rep docs.count docs.deleted store.size pri.store.size
yellow open   .kibana sny6Sj_JS6CaYEV079oAQg   1   1          1            0      3.1kb          3.1kb

4、商品的CRUD操作

（1）新增商品：新增文檔，建立索引

#模板：
PUT /index/type/id
{
  "json數(shù)據(jù)"
}
#實(shí)操：
PUT /ecommerce/product/1
{
    "name" : "gaolujie yagao",
    "desc" :  "gaoxiao meibai",
    "price" :  30,
    "producer" :      "gaolujie producer",
    "tags": [ "meibai", "fangzhu" ]
}
#返回結(jié)果：
{
  "_index": "ecommerce",  //索引
  "_type": "product",  //類型
  "_id": "1",  
  "_version": 1,  //版本號(hào)
  "result": "created",  //操作類型
  "_shards": {  //寫(xiě)到shard中
    "total": 2,  //寫(xiě)到2個(gè)shard中
    "successful": 1,  //成功寫(xiě)到1個(gè)shard中
    "failed": 0
  },
  "created": true
}

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" ]
}

es會(huì)自動(dòng)建立index和type，不需要提前創(chuàng)建，而且es默認(rèn)會(huì)對(duì)document每個(gè)field都建立倒排索引，讓其可以被搜索

（2）查詢商品：檢索文檔

#模板
GET /index/type/id
#實(shí)操
GET /ecommerce/product/1
#返回值
{
  "_index": "ecommerce",
  "_type": "product",
  "_id": "1",
  "_version": 1,
  "found": true,  //是否找到
  "_source": {
    "name": "gaolujie yagao",
    "desc": "gaoxiao meibai",
    "price": 30,
    "producer": "gaolujie producer",
    "tags": [
      "meibai",
      "fangzhu"
    ]
  }
}

（3）修改商品：替換文檔

#實(shí)操
PUT /ecommerce/product/1
{
    "name" : "jiaqiangban gaolujie yagao",
    "desc" :  "gaoxiao meibai",
    "price" :  30,
    "producer" :      "gaolujie producer",
    "tags": [ "meibai", "fangzhu" ]
}
#返回值
{
  "_index": "ecommerce",
  "_type": "product",
  "_id": "1",
  "_version": 2,
  "result": "updated",
  "_shards": {
    "total": 2,
    "successful": 1,
    "failed": 0
  },
  "created": false
}

#錯(cuò)誤的方式
PUT /ecommerce/product/1
{
    "name" : "jiaqiangban gaolujie yagao"
}

替換方式有一個(gè)不好，即使必須帶上所有的field，才能去進(jìn)行信息的修改

（4）修改商品：更新文檔

#實(shí)操
POST /ecommerce/product/1/_update
{
  "doc": {
    "name": "jiaqiangban gaolujie yagao"
  }
}
#返回值
{
  "_index": "ecommerce",
  "_type": "product",
  "_id": "1",
  "_version": 8,
  "result": "updated",
  "_shards": {
    "total": 2,
    "successful": 1,
    "failed": 0
  }
}

（5）刪除商品：刪除文檔

#實(shí)操
DELETE /ecommerce/product/1
#返回值
{
  "found": true,
  "_index": "ecommerce",
  "_type": "product",
  "_id": "1",
  "_version": 9,
  "result": "deleted",
  "_shards": {
    "total": 2,
    "successful": 1,
    "failed": 0
  }
}
#查詢后的返回值
{
  "_index": "ecommerce",
  "_type": "product",
  "_id": "1",
  "found": false
}