Search Template – 解耦程序 & 搜索 DSL

Elasticsearch 的查询语句
对相关性算分 / 查询性能都⾄关重要
在开发初期，虽然可以明确查询参数，但是往往还不能最终定义查询的DSL的具体结构
通过 Search Template 定义⼀个 Contract
各司其职，解耦
开发⼈员 / 搜索⼯程师 / 性能⼯程师

POST _scripts/tmdb
{
  "script": {
    "lang": "mustache",
    "source": {
      "_source": [
        "title","overview"
      ],
      "size": 20,
      "query": {
        "multi_match": {
          "query": "{{q}}",
          "fields": ["title","overview"]
        }
      }
    }
  }
}

使⽤ Search Template 进⾏查询

POST tmdb/_search/template
{
    "id":"tmdb",
    "params": {
        "q": "basketball with cartoon aliens"
    }
}

Index Alias 实现零停机运维

image.png

使⽤ Alias 创建不同查询的视图

POST _aliases
{
  "actions": [
    {
      "add": {
        "index": "movies-2019",
        "alias": "movies-lastest-highrate",
        "filter": {
          "range": {
            "rating": {
              "gte": 4
            }
          }
        }
      }
    }
  ]
}

本节知识点回顾

Search Template 的使⽤场景
如果通过 Mocha 语法定义⼀个 Search Template
Index Alias 的使⽤场景
如何创建与使⽤ Index Alias
通过 Index Alias 创建不同的查询视图

课程Demo

POST _scripts/tmdb
{
  "script": {
    "lang": "mustache",
    "source": {
      "_source": [
        "title","overview"
      ],
      "size": 20,
      "query": {
        "multi_match": {
          "query": "{{q}}",
          "fields": ["title","overview"]
        }
      }
    }
  }
}
DELETE _scripts/tmdb

GET _scripts/tmdb

POST tmdb/_search/template
{
    "id":"tmdb",
    "params": {
        "q": "basketball with cartoon aliens"
    }
}


PUT movies-2019/_doc/1
{
  "name":"the matrix",
  "rating":5
}

PUT movies-2019/_doc/2
{
  "name":"Speed",
  "rating":3
}

POST _aliases
{
  "actions": [
    {
      "add": {
        "index": "movies-2019",
        "alias": "movies-latest"
      }
    }
  ]
}

POST movies-latest/_search
{
  "query": {
    "match_all": {}
  }
}

POST _aliases
{
  "actions": [
    {
      "add": {
        "index": "movies-2019",
        "alias": "movies-lastest-highrate",
        "filter": {
          "range": {
            "rating": {
              "gte": 4
            }
          }
        }
      }
    }
  ]
}

POST movies-lastest-highrate/_search
{
  "query": {
    "match_all": {}
  }
}

Index Alias 经测试，可以对不同的索引起相同的别名

#Index Alias 经测试，可以对不同的索引起相同的别名
#alias可以指定多个index，但是只能指定一个index用于写入数据

DELETE /titles
DELETE /titles2
PUT /titles
{
  "mappings": {
    "properties": {
      "title": {
        "type": "text",
        "analyzer": "english"
      }
    }
  }
}
PUT /titles2
{
  "mappings": {
    "properties": {
      "title": {
        "type": "text",
        "analyzer": "english",
        "fields": {"std": {"type": "text","analyzer": "standard"}}
      }
    }
  }
}
POST titles/_bulk
{ "index": { "_id": 1 }}
{ "title": "My dog barks" }
{ "index": { "_id": 2 }}
{ "title": "I see a lot of barking dogs on the road " }
POST titles2/_bulk
{ "index": { "_id": 3 }}
{ "title": "My dog barks" }
{ "index": { "_id": 4 }}
{ "title": "I see a lot of barking dogs on the road " }
POST _aliases
{
  "actions": [
    {
      "add": {
        "index": "titles",
        "alias": "aliastitle"
      }
    }
  ]
}
POST _aliases
{
  "actions": [
    {
      "add": {
        "index": "titles2",
        "alias": "aliastitle"
      }
    }
  ]
}
GET /aliastitle/_search
{
   "query": {
        "multi_match": {
            "query": "barking dogs",
            "type": "most_fields",
            "fields": [ "title", "title.std" ]
        }
    }
}
GET /aliastitle/_search
{
   "query": {
        "multi_match": {
            "query": "barking dogs",
            "type": "most_fields",
            "fields": [ "title^10", "title.std" ]
        }
    }
}