Elasticsearch 7：快速上手

#Elasticsearch

截止2019-06-28，ES最新版是 7.2.0 。

可以进入 https://www.elastic.co/cn/downloads/past-releases 如果要下载指定版本的安装包。

安装

前置条件是安装 Java。

然后去 ES 官网下载 ES。下载地址。ES 的最新版本是 7.2.0。

下载后，解压。

启动

$ cd elasticsearch-7.2.0
$ ./bin/elasticsearch

关于 Index、Type、Document

• Index 对应 MySQL 中的 Database；
• Type 对应 MySQL 中的 Table；
• Document 对应 MySQL 中表的记录。

在 7.0 以及之后的版本中 Type 被废弃了。（其实还可以用，但是已经不推荐了）

一个MySQL实例中可以创建多个 Database，一个Database中可以创建多个Table。

ES 的Type 被废弃后：

• ES 实例：对应 MySQL 实例中的一个 Database。
• Index 对应 MySQL 中的 Table 。
• Document 对应 MySQL 中表的记录。

Index 的复数是 Indices。

使用 curl 命令操作与 ES 交互

查看信息：

$ curl http://localhost:9200

{
  "name" : "Myhost",
  "cluster_name" : "elasticsearch",
  "cluster_uuid" : "abtEL4GKRfulSwTfJ0wX5Q",
  "version" : {
    "number" : "7.2.0",
    "build_flavor" : "default",
    "build_type" : "tar",
    "build_hash" : "508c38a",
    "build_date" : "2019-06-20T15:54:18.811730Z",
    "build_snapshot" : false,
    "lucene_version" : "8.0.0",
    "minimum_wire_compatibility_version" : "6.8.0",
    "minimum_index_compatibility_version" : "6.0.0-beta1"
  },
  "tagline" : "You Know, for Search"
}

查看所有的 Index

$ curl 'localhost:9200/_mapping?pretty=true'

{ }

创建 Index

使用 HTTP PUT 请求创建 Index：

$ curl -X PUT 'localhost:9200/school?pretty=true'

{
    "acknowledged":true,
    "shards_acknowledged":true,
    "index":"school"
}

再次查询所有 Index：

▶ curl 'localhost:9200/_mapping?pretty=true'
{
  "school" : {
    "mappings" : { }
  }
}

删除 Index

使用 HTTP DELETE 请求删除 Index：

$ curl -X DELETE 'localhost:9200/school?pretty=true'
{
  "acknowledged" : true
}

新增记录

虽然 ES 7 中废弃了 Type 的概念，但是新增数据时仍然可以指定 Type 。这只是为了过渡期的兼容，因为大部分接口已经不支持了。

$ curl -X POST -H "Content-Type: application/json" 'localhost:9200/school/student/1?pretty=true' -d '
{
  "name": "张三"
}' 

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

$ curl -X POST -H "Content-Type: application/json" 'localhost:9200/school/student/?pretty=true' -d '
{
  "name": "李四"
}'

{
  "_index" : "school",
  "_type" : "student",
  "_id" : "Qeg8omsBnXt8WY5cFy3z",
  "_version" : 1,
  "result" : "created",
  "_shards" : {
    "total" : 2,
    "successful" : 1,
    "failed" : 0
  },
  "_seq_no" : 1,
  "_primary_term" : 1
}

再次查看 mapping：

▶ curl 'localhost:9200/_mapping?pretty=true'
{
  "school" : {
    "mappings" : {
      "properties" : {
        "name" : {
          "type" : "text",
          "fields" : {
            "keyword" : {
              "type" : "keyword",
              "ignore_above" : 256
            }
          }
        }
      }
    }
  }
}

注意，查询结果中并没有 student 这个type。

更合理的做法应该是：

curl -X POST -H "Content-Type: application/json" 'localhost:9200/school/_doc/1?pretty=true' -d '
{
  "name": "王五"
}' 

查询记录

▶ curl 'localhost:9200/school/student/1?pretty=true'
{
  "_index" : "school",
  "_type" : "student",
  "_id" : "1",
  "_version" : 1,
  "_seq_no" : 0,
  "_primary_term" : 1,
  "found" : true,
  "_source" : {
    "name" : "张三"
  }
}

▶ curl 'localhost:9200/school/student/Qeg8omsBnXt8WY5cFy3z?pretty=true'
{
  "_index" : "school",
  "_type" : "student",
  "_id" : "Qeg8omsBnXt8WY5cFy3z",
  "_version" : 1,
  "_seq_no" : 1,
  "_primary_term" : 1,
  "found" : true,
  "_source" : {
    "name" : "李四"
  }
}

查找不存在的记录：

▶ curl 'localhost:9200/school/student/123?pretty=true'
{
  "_index" : "school",
  "_type" : "student",
  "_id" : "123",
  "found" : false
}

查看所有记录：

$ curl -X GET -H "Content-Type: application/json" 'localhost:9200/school/student/_search?size=50&pretty=true' -d '
{
    "query" : {
        "match_all" : {}
    }
}'

{
  "took" : 6,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 2,
      "relation" : "eq"
    },
    "max_score" : 1.0,
    "hits" : [
      {
        "_index" : "school",
        "_type" : "student",
        "_id" : "1",
        "_score" : 1.0,
        "_source" : {
          "name" : "张三"
        }
      },
      {
        "_index" : "school",
        "_type" : "student",
        "_id" : "Qeg8omsBnXt8WY5cFy3z",
        "_score" : 1.0,
        "_source" : {
          "name" : "李四"
        }
      }
    ]
  }
}

更新记录

curl -X POST -H "Content-Type: application/json" 'localhost:9200/school/student/1?pretty=true' -d '
{
  "name": "张三换名字了"
}' 

{
  "_index" : "school",
  "_type" : "student",
  "_id" : "1",
  "_version" : 2,
  "result" : "updated",
  "_shards" : {
    "total" : 2,
    "successful" : 1,
    "failed" : 0
  },
  "_seq_no" : 2,
  "_primary_term" : 1
}

▶ curl 'localhost:9200/school/student/1?pretty=true'
{
  "_index" : "school",
  "_type" : "student",
  "_id" : "1",
  "_version" : 2,
  "_seq_no" : 2,
  "_primary_term" : 1,
  "found" : true,
  "_source" : {
    "name" : "张三换名字了"
  }
}

删除记录

先创建一条记录：

curl -X POST -H "Content-Type: application/json" 'localhost:9200/school/student/?pretty=true' -d '
{
  "name": "测试用户"
}' 

{
  "_index" : "school",
  "_type" : "student",
  "_id" : "QuhJomsBnXt8WY5cGi2q",
  "_version" : 1,
  "result" : "created",
  "_shards" : {
    "total" : 2,
    "successful" : 1,
    "failed" : 0
  },
  "_seq_no" : 3,
  "_primary_term" : 1
}

查询：

curl 'localhost:9200/school/student/QuhJomsBnXt8WY5cGi2q?pretty=true'

{
  "_index" : "school",
  "_type" : "student",
  "_id" : "QuhJomsBnXt8WY5cGi2q",
  "_version" : 1,
  "_seq_no" : 3,
  "_primary_term" : 1,
  "found" : true,
  "_source" : {
    "name" : "测试用户"
  }
}

删除：

curl -X DELETE 'localhost:9200/school/student/QuhJomsBnXt8WY5cGi2q?pretty=true'

{
  "_index" : "school",
  "_type" : "student",
  "_id" : "QuhJomsBnXt8WY5cGi2q",
  "_version" : 2,
  "result" : "deleted",
  "_shards" : {
    "total" : 2,
    "successful" : 1,
    "failed" : 0
  },
  "_seq_no" : 4,
  "_primary_term" : 1
}

再次查询：

▶ curl 'localhost:9200/school/student/QuhJomsBnXt8WY5cGi2q?pretty=true'
{
  "_index" : "school",
  "_type" : "student",
  "_id" : "QuhJomsBnXt8WY5cGi2q",
  "found" : false
}

kibana 简单入门

安装

到官网下载 kibana，解压。

启动

▶ cd kibana-7.2.0
▶ ./bin/kibana

使用 Dev Tools 查询

进入 http://localhost:5601 ，选择 Dev tools。或者直接进入 http://localhost:5601/app/kibana#/dev_tools 。

运行：

GET /school/_mapping

输出：

{
  "school" : {
    "mappings" : {
      "properties" : {
        "name" : {
          "type" : "text",
          "fields" : {
            "keyword" : {
              "type" : "keyword",
              "ignore_above" : 256
            }
          }
        }
      }
    }
  }
}

运行：

GET /school/student/_search
{
  "query": {
    "match_all": {}
  }
}

输出：

#! Deprecation: [types removal] Specifying types in search requests is deprecated.
{
  "took" : 0,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 2,
      "relation" : "eq"
    },
    "max_score" : 1.0,
    "hits" : [
      {
        "_index" : "school",
        "_type" : "student",
        "_id" : "1",
        "_score" : 1.0,
        "_source" : {
          "name" : "张三换名字了"
        }
      },
      {
        "_index" : "school",
        "_type" : "student",
        "_id" : "Qeg8omsBnXt8WY5cFy3z",
        "_score" : 1.0,
        "_source" : {
          "name" : "李四"
        }
      }
    ]
  }
}

运行：

GET /school/student/1

输出：

#! Deprecation: [types removal] Specifying types in document get requests is deprecated, use the /{index}/_doc/{id} endpoint instead.
{
  "_index" : "school",
  "_type" : "student",
  "_id" : "1",
  "_version" : 2,
  "_seq_no" : 2,
  "_primary_term" : 1,
  "found" : true,
  "_source" : {
    "name" : "张三换名字了"
  }
}

GET /school/student/1 这种方式要被废弃了，可以换成 GET /school/_doc/1 。

查询 name 中含有李的记录：

GET /school/student/_search
{
  "query": {
    "match": {"name": "李"}
  }
}

使用 Dev tools 添加记录

运行：

POST /school/student
{
  "name": "王五"
}

输出：

#! Deprecation: [types removal] Specifying types in document index requests is deprecated, use the typeless endpoints instead (/{index}/_doc/{id}, /{index}/_doc, or /{index}/_create/{id}).
{
  "_index" : "school",
  "_type" : "student",
  "_id" : "PKoco2sBUDoa-284Kvwn",
  "_version" : 1,
  "result" : "created",
  "_shards" : {
    "total" : 2,
    "successful" : 1,
    "failed" : 0
  },
  "_seq_no" : 5,
  "_primary_term" : 2
}

可以看到POST /school/student已经被废弃了（虽然现在还是支持的）。

我们用新的方式创建。

运行：

POST /school/_doc/
{
  "name": "李白"
}

输出：

{
  "_index" : "school",
  "_type" : "_doc",
  "_id" : "Paofo2sBUDoa-284nvzx",
  "_version" : 1,
  "result" : "created",
  "_shards" : {
    "total" : 2,
    "successful" : 1,
    "failed" : 0
  },
  "_seq_no" : 6,
  "_primary_term" : 2
}

其实就是 type 是 _doc，这是 ES 团队选择的一种废弃Type的方案。上文中我们用 curl 命令操作文档，type 的值换成 _doc即可。

参考链接

• 全文搜索引擎 Elasticsearch 入门教程

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