Search API

• URI Search: uri 中带参数
• Request Body search: es 提供，基于json格式更加完备的DSL

指定查询索引

• /_search ：集群上所有索引
• /index1,index2/_doc/_search ：index1,index2 索引
• /index*/_doc/_search ：以index开头的索引

请求后响应

• took: 花费时间
• total: 符合条件的总文档数
• hits: 结果集，默认前十
• _source: 文档原始信息

搜索相关性

• 搜索是用户和搜索引擎的对话
• 用户关系搜索结果的相关性
  • 是否可以找到搜索相关内容
  • 有多少部相关内容被返回
  • 文档打分排序是否合理
  • 结合业务需求，平衡结果排名

Page Rank 算法

• 不仅仅是内容
• 更重要的内容可信度

网站搜索引擎，其实是 销售的角色

• 提升销售业绩
• 去除库存

衡量相关性

• 查准率 - 尽可能返回较少无关文档
• 查全率 - 尽量返回较多的相关文档
• 排名 - 是否能按照相关度进行排序

文档的基本 CRUD 与批量操作

课程Demo

############Create Document############
#create document. 自动生成 _id
POST users/_doc
{
	"user" : "Mike",
    "post_date" : "2019-04-15T14:12:12",
    "message" : "trying out Kibana"
}

#create document. 指定Id。如果id已经存在，报错
PUT users/_doc/1?op_type=create
{
    "user" : "Jack",
    "post_date" : "2019-05-15T14:12:12",
    "message" : "trying out Elasticsearch"
}

#create document. 指定 ID 如果已经存在，就报错
PUT users/_create/1
{
     "user" : "Jack",
    "post_date" : "2019-05-15T14:12:12",
    "message" : "trying out Elasticsearch"
}

### Get Document by ID
#Get the document by ID
GET users/_doc/1


###  Index & Update
#Update 指定 ID  (先删除，在写入)
GET users/_doc/1

PUT users/_doc/1
{
	"user" : "Mike"

}


#GET users/_doc/1
#在原文档上增加字段
POST users/_update/1/
{
    "doc":{
        "post_date" : "2019-05-15T14:12:12",
        "message" : "trying out Elasticsearch"
    }
}



### Delete by Id
# 删除文档
DELETE users/_doc/1


### Bulk 操作
#执行两次，查看每次的结果

#执行第1次
POST _bulk
{ "index" : { "_index" : "test", "_id" : "1" } }
{ "field1" : "value1" }
{ "delete" : { "_index" : "test", "_id" : "2" } }
{ "create" : { "_index" : "test2", "_id" : "3" } }
{ "field1" : "value3" }
{ "update" : {"_id" : "1", "_index" : "test"} }
{ "doc" : {"field2" : "value2"} }


#执行第2次
POST _bulk
{ "index" : { "_index" : "test", "_id" : "1" } }
{ "field1" : "value1" }
{ "delete" : { "_index" : "test", "_id" : "2" } }
{ "create" : { "_index" : "test2", "_id" : "3" } }
{ "field1" : "value3" }
{ "update" : {"_id" : "1", "_index" : "test"} }
{ "doc" : {"field2" : "value2"} }

### mget 操作
GET /_mget
{
    "docs" : [
        {
            "_index" : "test",
            "_id" : "1"
        },
        {
            "_index" : "test",
            "_id" : "2"
        }
    ]
}


#URI中指定index
GET /test/_mget
{
    "docs" : [
        {

            "_id" : "1"
        },
        {

            "_id" : "2"
        }
    ]
}


GET /_mget
{
    "docs" : [
        {
            "_index" : "test",
            "_id" : "1",
            "_source" : false
        },
        {
            "_index" : "test",
            "_id" : "2",
            "_source" : ["field3", "field4"]
        },
        {
            "_index" : "test",
            "_id" : "3",
            "_source" : {
                "include": ["user"],
                "exclude": ["user.location"]
            }
        }
    ]
}

### msearch 操作
POST kibana_sample_data_ecommerce/_msearch
{}
{"query" : {"match_all" : {}},"size":1}
{"index" : "kibana_sample_data_flights"}
{"query" : {"match_all" : {}},"size":2}


### 清除测试数据
#清除数据
DELETE users
DELETE test
DELETE test2

相关阅读

• Document API https://www.elastic.co/guide/en/elasticsearch/reference/7.1/docs.html
• https://www.elastic.co/guide/en/elasticsearch/reference/7.1/search-search.html
• https://searchenginewatch.com/sew/news/2065080/search-engines-101
• https://www.huffpost.com/entry/search-engines-101-part-i_b_1104525
• https://www.entrepreneur.com/article/176398
• https://www.searchtechnologies.com/meaning-of-relevancy
• https://baike.baidu.com/item/搜索引擎发展史/2422574