Elasticsearch入门教程之安装与基本使用

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2019-5-10

ubuntu16.04+elasticsearch6.5为例,参考官网文档https://www.elastic.co/guide/en/elasticsearch/reference/current/getting-started.html

安装java

参考文章:https://www.digitalocean.com/community/tutorials/how-to-install-java-with-apt-get-on-ubuntu-16-04

$ sudo apt-get update
$ sudo apt-get install -y default-jre
$ sudo add-apt-repository ppa:webupd8team/java && sudo apt-get update
$ sudo apt-get install oracle-java8-installer
$ export JAVA_HOME="/usr/lib/jvm/java-8-oracle"
$ java -version     #测试java
$ echo $JAVA_HOME   #测试java_home

Elasticsearch

安装(6.5.4)

$ wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-6.5.4.zip
$ unzip elasticsearch-6.5.4.zip

启动

$ cd elasticsearch-6.5.4/bin
$ ./elasticsearch   

启动时,如果报错vm.maxmapcount [65530] is too low执行下面

$ sudo sysctl -w vm.max_map_count=262144

curl测试,出现以下信息表示启动成功,安装正常

$ curl 127.0.0.1:9200   
{
  "name" : "c5skAub",
  "cluster_name" : "elasticsearch",
  "cluster_uuid" : "bdkUuVtQSvWOiY_vXEFnvw",
  "version" : {
    "number" : "6.5.4",
    "build_flavor" : "default",
    "build_type" : "tar",
    "build_hash" : "d2ef93d",
    "build_date" : "2018-12-17T21:17:40.758843Z",
    "build_snapshot" : false,
    "lucene_version" : "7.5.0",
    "minimum_wire_compatibility_version" : "5.6.0",
    "minimum_index_compatibility_version" : "5.0.0"
  },
  "tagline" : "You Know, for Search"
}   

基础概念

Elastic是目前全文搜索引擎的首选,本质上是非关系型数据库,与mysql一些概念对比如下。

Mysql Elastic
database(数据库) index(索引)
table(表) type(类型,7.x将废弃)
row(记录) document(文档)
column(字段) fileds(字段)

基本操作

Elastic的操作通过rest api来完成,以下操作都将省去curl -XMETHOD "http://localhost:9200" -H 'Content-Type: application/json' [-d 'request body'],如果想远程访问,修改/path-to-elastic/config/elasticsearch.yml中的network.host: 0.0.0.0后重启即可

操作索引

新建一个名为customer的index,?pretty返回友好的json

$ PUT /customer?pretty  

列出所有索引

$ GET /_cat/indices?v 

删除索引

$ DELETE /customer
操作文档

新建id为1的document,由于type将被废除,所以规定每个index只包含一个type,统一为_doc

$ PUT /customer/_doc/1?pretty
{
    "name": "luke"
}

如果使用post并且id留空将会生成一个随机的id

$ POST /customer/_doc?pretty {"name": "php"}
{
    "_index": "customer",
    "_type": "_doc",
    "_id": "hIkkLGgBFVhvdLuiNNGD",  ##返回的id
    "_version": 1,
    "result": "created",
    "_shards": {
        "total": 2,
        "successful": 1,
        "failed": 0
    },
    "_seq_no": 0,
    "_primary_term": 3
}

更新文档与新建相同,改变数据即可,或者

$ POST /customer/_doc/1/_update?pretty
{
    "doc": { "name": "luke44", "age": 24 }
}

使用简单的脚本更新,这里的ctx._source指向将被修改的文档

$ POST /customer/_doc/1/_update?pretty
{
  "script" : "ctx._source.age += 5"
}

查询id为1的文档

$ GET /customer/_doc/1?pretty
{
    "_index": "customer",
    "_type": "_doc",
    "_id": "1",
    "_version": 1,
    "found": true,
    "_source": {
        "name": "luke"
    }
}

删除文档

$ DELETE /customer/_doc/2?pretty

批量操作,批量更新id为1和2的文档,注意在postman中body最后必须空一行

$ POST /customer/_doc/_bulk?pretty
{"index":{"_id":"1"}}
{"name": "luke" }
{"index":{"_id":"2"}}
{"name": "php", "age": "20" }

先更新id为1的文档,然后删除id为2的文档

$ POST /customer/_doc/_bulk?pretty
{"update":{"_id":"1"}}
{"doc":{"name":"php best"}}
{"delete":{"_id":"2"}}

批量操作时其中一个操作失败时,其他操作任然会继续执行,结束时根据执行顺序返回状态。

浏览数据

先准备一个虚拟的银行客户帐户信息数据集,类似这种格式,请右键下载数据集另存为accounts.json

{
    "account_number": 0,
    "balance": 16623,
    "firstname": "Bradshaw",
    "lastname": "Mckenzie",
    "age": 29,
    "gender": "F",
    "address": "244 Columbus Place",
    "employer": "Euron",
    "email": "bradshawmckenzie@euron.com",
    "city": "Hobucken",
    "state": "CO"
}
导入数据集
$ POST /bank/_doc/_bulk?pretty&refresh --data-binary "@accounts.json"
$ GET /_cat/indices?v
health status index    uuid                   pri rep docs.count docs.deleted store.size pri.store.size
yellow open   bank     3inMmuQzRqaTpMkzfh07_A   5   1       1000            0     95.9kb         95.9kb
yellow open   customer gSRgPG9cScKHcuycJE2drw   5   1          2            0      7.7kb          7.7kb
match_all查询

使用URI搜索,q=*匹配所有,sort=account_number:asc表示按account_number升序排列

$ GET /bank/_search?q=*&sort=account_number:asc&pretty
{
  "took" : 63,  //耗时,毫秒
  "timed_out" : false,  //是否超时
  "_shards" : {     //碎片
    "total" : 5,
    "successful" : 5,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {    //命中
    "total" : 1000,
    "max_score" : null,
    "hits" : [ {
      "_index" : "bank",
      "_type" : "_doc",
      "_id" : "0",
      "sort": [0],
      "_score" : null,
      "_source" : {"account_number":0,"balance":16623,"firstname":"Bradshaw","lastname":"Mckenzie","age":29,"gender":"F","address":"244 Columbus Place","employer":"Euron","email":"bradshawmckenzie@euron.com","city":"Hobucken","state":"CO"}
    }, {
      "_index" : "bank",
      "_type" : "_doc",
      "_id" : "1",
      "sort": [1],
      "_score" : null,
      "_source" : {"account_number":1,"balance":39225,"firstname":"Amber","lastname":"Duke","age":32,"gender":"M","address":"880 Holmes Lane","employer":"Pyrami","email":"amberduke@pyrami.com","city":"Brogan","state":"IL"}
    }, ...
    ]
  }
}

使用json请求体搜索,获取跟上面相同的效果

$ GET /bank/_search
{
  "query": { "match_all": {} },
  "sort": [
    { "account_number": "asc" }
  ]
}

使用size和from限制结果条数,类似mysql的limit和from;使用_source查询指定字段

$ GET /bank/_search
{
  "query": { "match_all": {} },
  "sort": { "balance": { "order": "desc" } },
  "from": 10,
  "size": 15,    //默认10
  "_source": ["account_number", "balance"]
}
match查询

查询account_number为20的所有账户

$ GET /bank/_search
{
  "query": { "match": { "account_number": 20 } }
}

查询address中包含mill单词的所有账户

$ GET /bank/_search
{
  "query": { "match": { "address": "mill" } }
}

查询address中包含mill或者lane单词的所有账户

$ GET /bank/_search
{
  "query": { "match": { "address": "mill lane" } }
}

match_phrase查询,match的变种,查询address中包含mill lane的所有账户

$ GET /bank/_search
{
  "query": { "match_phrase": { "address": "mill lane" } }
}
bool查询

查询address中包含milllane单词的所有账户,bool must子句指定所有必须为true的查询才能将文档视为匹配项

$ GET /bank/_search
{
  "query": {
    "bool": {
      "must": [
        { "match": { "address": "mill" } },
        { "match": { "address": "lane" } }
      ]
      //"should": [...] 或查询
      //"must_not": [...] 都不是
    }
  }
}

组合查询,查询年龄为40并且不住在ID省的客户账户

$ GET /bank/_search
{
  "query": {
    "bool": {
      "must": [
        { "match": { "age": "40" } }
      ],
      "must_not": [
        { "match": { "state": "ID" } }
      ]
    }
  }
}
bool过滤器

查询余额在20000到30000(包含)的客户账户

$ GET /bank/_search
{
  "query": {
    "bool": {
      "must": { "match_all": {} },
      "filter": {
        "range": {
          "balance": {
            "gte": 20000,
            "lte": 30000
          }
        }
      }
    }
  }
}
Elasticsearch是一个既简单又复杂的工具。以上,已经了解了它的基础知识,以及如何使用一些REST API来处理它,以后再慢慢了解一些更高级的知识点。

作者:luke_44