Elasticsearch 备忘清单
===
这是 [Elasticsearch](https://www.elastic.co/guide/index.html) 的官方文档。 你可以在这里找到 elasticsearch 的所有文档。
入门
---
### 入门
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Elasticsearch 是一个基于 Lucene 库的搜索引擎。它提供了一个分布式、支持多租户的全文搜索引擎，具有HTTP Web接口和无模式JSON文档。
#### 下载
注意： `${VERSION}` 需替换为指定版本，官方包有的功能只能试用，完整功能需要付费，请仔细阅读官网文档。
#### Windows
```
https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-${VERSION}-windows-x86_64.zip
```
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#### linux
```shell
$ wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-${VERSION}-linux-x86_64.tar.gz
$ wget https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-${VERSION}-linux-x86_64.tar.gz.sha512
$ shasum -a 512 -c elasticsearch-${VERSION}-linux-x86_64.tar.gz.sha512
$ tar -xzf elasticsearch-${VERSION}-linux-x86_64.tar.gz
$ cd elasticsearch-${VERSION}/
```
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#### macos
```shell
$ curl -O https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-${VERSION}-darwin-x86_64.tar.gz
$ curl https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-${VERSION}-darwin-x86_64.tar.gz.sha512 | shasum -a 512 -c -
$ tar -xzf elasticsearch-${VERSION}-darwin-x86_64.tar.gz
$ cd elasticsearch-${VERSION}/
```
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### 启动
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- 启动 Elasticsearch
```shell
$ ./bin/elasticsearch
```
- 设置密码
```shell
export ELASTIC_PASSWORD="your_password"
```
- 测试是否启动成功
```shell
curl --cacert $ES_HOME/config/certs/http_ca.crt -u elastic:$ELASTIC_PASSWORD https://localhost:9200
```
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- 成功则返回样例如下:
```json
{
"name" : "Cp8oag6",
"cluster_name" : "elasticsearch",
"cluster_uuid" : "AT69_T_DTp-1qgIJlatQqA",
"version" : {
"number" : "${VERSION}",
"build_type" : "tar",
"build_hash" : "f27399d",
"build_flavor" : "default",
"build_date" : "2016-03-30T09:51:41.449Z",
"build_snapshot" : false,
"lucene_version" : "9.10.0",
"minimum_wire_compatibility_version" : "1.2.3",
"minimum_index_compatibility_version" : "1.2.3"
},
"tagline" : "You Know, for Search"
}
```
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### Elasticsearch 和 RDMS 的对比
| RDMS | elasticsearch |
| ----------------------- | ----------------- |
| 数据库(database) | 索引(index) |
| 表(table) | 类型(type) |
| 行(row) | 文档(document) |
| 列(column) | 字段(field) |
| 表结构 | 映射 |
| 索引 | 全文索引 |
| SQL | 查询DSL |
| SELECT * FROM tablename | GET http://... |
| UPDATE table SET | PUT http://... |
| DELETE | DELETE http://... |
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操作
---
### 基础语法规则
```shell
$ curl -X<VERB> '<PROTOCOL>://<HOST>:<PORT>/<PATH>?<QUERY_STRING>' -d '<BODY>'
```
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- `VERB HTTP` 方法：GET, POST, PUT, HEAD, DELETE
- `PROTOCOL`：http 或者 https 协议（只有在 Elasticsearch 前面有 https 代理的时候可用）
- `HOST`：Elasticsearch 集群中的任何一个节点的主机名，如果是在本地的节点，那么就叫 localhost
- `PORT`：Elasticsearch HTTP 服务所在的端口，默认为 9200
- `PATH API 路径`（例如_count 将返回集群中文档的数量），PATH：可以包含多个组件，例如_cluster/stats 或者_nodes/stats/jvm
- `QUERY_STRING`：一些可选的查询请求参数，例如?pretty 参数将使请求返回更加美观易读的 JSON 数据
- `BODY`：一个 JSON 格式的请求主体（如果请求需要的话）
### 创建索引
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#### 统一请求 api 前缀
```
http://localhost:9200/
```
#### DSL语法
```json
PUT /user_info
{
"settings": { "number_of_replicas": 1, "number_of_shards": 1 },
"mappings": {
"properties": {
"id": { "type": "long", "index": true },
"username": { "type": "keyword", "index": true },
"nickname": { "type": "keyword", "index": true },
"password": { "type": "keyword", "index": false },
"age": { "type": "integer", "index": true },
"info": { "type": "text", "index": true },
"remark": { "type": "text", "index": true }
}
}
}
```
#### curl
```shell
curl -XPUT "http://localhost:9200/user_info" -H 'Content-Type: application/json' -d'{ "settings": { "number_of_replicas": 1, "number_of_shards": 1 }, "mappings": { "properties": { "id": { "type": "long", "index": true }, "username": { "type": "keyword", "index": true }, "nickname": { "type": "keyword", "index": true }, "password": { "type": "keyword", "index": false }, "age": { "type": "integer", "index": true }, "info": { "type": "text", "index": true }, "remark": { "type": "text", "index": true } } } }'
```
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#### 参数说明
- `settings`: 设置索引的信息
- `number_of_shards`: 每个索引的主分片数，一旦索引创建后，无法修改此配置
- `number_of_replicas`: 每个主分片的副本数，此配置可随时修改
- `mappings`: 索引映射定义
- `properties`: 字段定义。使用 JSON 配置，键为字段名称（自定义），值为嵌套 JSON，其中 `type` 指定字段的类型
其他参数很多，请参考官网资料
### 删除索引
#### DSL语法
```http
DELETE /user_info
```
#### curl
```shell
curl -XDELETE "http://localhost:9200/user_info"
```
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### 判断索引是否存在
#### DSL语法
```http
# 查看索引是否存在
HEAD /user_info
```
#### curl
```shell
# 查看索引是否存在
curl -XHEAD "http://localhost:9200/user_info"
```
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### 开启/关闭索引
#### 开启DSL语法
```shell
POST /user_info/_open
```
`curl`
```shell
curl -XPOST "http://localhost:9200/user_info/_open"
```
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#### 关闭 DSL 语法
```shell
POST /user_info/_close
```
`curl`
```shell
curl -XPOST "http://localhost:9200/user_info/_close"
```
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### 索引的别名
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- 添加别名 DSL 语法
```shell
POST /user_info/_alias/user1
```
```shell
curl -XPOST "http://localhost:9200/user_info/_alias/user1"
```
- 删除别名DSL语法
```shell
DELETE /user_info/_alias/user1
```
```shell
curl -XDELETE "http://localhost:9200/user_info/_alias/user1"
```
- 查看别名DSL语法
```shell
GET /_alias/user1
```
```shell
curl -XGET "http://localhost:9200/_alias/useraa"
```
Mapping 操作
---
类似修改数据库中列的操作
### 查看 mapping
#### DSL语法
```shell
GET /user_info/_mapping
```
---
```shell
curl -XGET "http://localhost:9200/user_info/_mapping"
```
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### 新增 mapping
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#### DSL语法
```shell
PUT /user_info/_mapping
{
"properties":{
"sex":{ "type":"keyword" }
}
}
```
---
```shell
curl -XPUT "http://localhost:9200/user_info/_mapping" -H 'Content-Type: application/json' -d'{ "properties":{ "sex":{ "type":"keyword" } } }'
```
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`注意`: 需要注意的是字段映射只能增加，不能更改删除
文档的操作
---
### 添加文档
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#### 新增一条数据 - DSL语法
```shell
POST /user_info/_doc/1
{
"id":1,
"username":"username",
"password":"123456",
"nickname":"nickname",
"age":18,
"info":"一些个人相关的介绍",
"remark":"备注信息",
"sex":"男"
}
```
---
```shell
curl -XPOST "http://localhost:9200/user_info/_doc/1" -H 'Content-Type: application/json' -d'{ "id":1, "username":"username", "password":"123456", "nickname":"nickname", "age":18, "info":"一些个人相关的介绍", "remark":"备注信息", "sex":"男" }'
```
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### 查询指定索引的所有文档
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类似数据库中的 `select * from user_info;`
#### DSL语法
```json
GET /user_info/_search
{
"query": {
"match_all": {}
}
}
```
---
```shell
curl -XGET "http://localhost:9200/user_info/_search" -H 'Content-Type: application/json' -d'{ "query": { "match_all": {} } }'
```
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### 通过 id 查询文档
类似数据库中的 `select * from user_info where id = 1;`
#### DSL语法
```shell
GET /user_info/_doc/1
```
---
```shell
curl -XGET "http://localhost:9200/user_info/_doc/1"
```
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### 模糊查找
类似数据库中的模糊查询 `select * from user_info where info like '%人%';`
#### DSL语法
```json
GET /user_info/_search
{
"query": { "match": { "info": "人" } }
}
```
### 通过条件查询文档
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类似数据库中的 `select * from user_info where username = 'username';`
#### 通过条件查询 - DSL语法
```json
GET /user_info/_search
{
"query": {
"bool": {
"must": [ { "term": { "username": "username" } } ]
}
}
}
```
---
```shell
curl -XGET "http://localhost:9200/user_info/_search" -H 'Content-Type: application/json' -d'{ "query": { "bool": { "must": [ { "term": { "username": "username" } } ] } } }'
```
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### 范围查找
类似数据库中的范围查询 `select * from user_info where age between 18 and 30;`
#### DSL语法
```json
GET /user_info/_search
{
"query": {
"range": {
"age": {
"gt": 18,
"lt": 30
}
}
}
}
```
---
```shell
curl -XGET "http://localhost:9200/user_info/_search" -H 'Content-Type: application/json' -d'{ "query": { "range": { "age": { "gt": 18, "lt": 30 } } } }'
```
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### and 查询
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类似数据库中的 and 查询 `select * from user_info where age > 18 and sex = '男';`
#### DSL语法
```json
GET /user_info/_search
{
"query": {
"bool": {
"must": [
{ "range": { "age": { "gt": 18 } } },
{ "term": { "sex": "男" } }
]
}
}
}
```
---
```shell
curl -XGET "http://localhost:9200/user_info/_search" -H 'Content-Type: application/json' -d'{ "query": { "bool": { "must": [ { "range": { "age": { "gt": 17 } } }, { "term": { "sex": "男" } } ] } } }'
```
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### limit 查找
类似数据库中的 limit 查询 `select * from user_info limit 10;`
#### DSL语法
```json
GET /user_info/_search
{
"size": 10,
"query": {
"match_all": {}
}
}
```
---
```shell
curl -XGET "http://localhost:9200/user_info/_search" -H 'Content-Type: application/json' -d'{ "size": 1, "query": { "match_all": {} } }'
```
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### limit offset 查找
类似数据库中的 limit 查询 `select * from user_info limit 0,10;`
#### DSL语法
```http
GET /user_info/_search
{
"size": 2,
"from": 1,
"query": {
"match_all": {}
}
}
```
---
```shell
curl -XGET "http://localhost:9200/user_info/_search" -H 'Content-Type: application/json' -d'{ "size": 2, "from": 1, "query": { "match_all": {} } }'
```
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#### 参数说明
- `size`: 10 表示我们想要返回的结果数量是10条
- `from`: 20 表示我们想要从结果集中的第21条记录开始返回（因为偏移是从0开始的）
- `query`: `{"match_all": {}}` 是一个匹配所有文档的查询，因为我们没有特定的查询条件，只是想要分页结果
### or 查询
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类似数据库中的 or 查询 `select * from user_info where age > 18 or sex = '男';`
#### DSL语法
```json
GET /user_info/_search
{
"query": {
"bool": {
"should": [
{
"range": {
"age": { "gt": 18 }
}
},
{
"term": { "sex": "男" }
}
]
}
}
}
```
---
```shell
curl -XGET "http://localhost:9200/user_info/_search" -H 'Content-Type: application/json' -d'{ "query": { "bool": { "should": [ { "range": { "age": { "gt": 18 } } }, { "term": { "sex": "男" } } ] } } }'
```
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删除文档
---
### 删除指定 id
类似数据库中的 delete 查询 `delete from user_info where id = 3;`
#### DSL语法
```shell
# 删除文档
DELETE /user_info/_doc/3
```
---
```shell
# 删除文档
curl -XDELETE "http://localhost:9200/user_info/_doc/3"
```
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### 删除指定条件
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类似数据库中的 delete 查询 `delete from user_info where age > 18;`
#### DSL语法
```json
POST /user_info/_delete_by_query
{
"query": {
"range": { "age": { "gt": 18 } }
}
}
```
---
```shell
curl -XPOST "http://localhost:9200/user_info/_delete_by_query" -H 'Content-Type: application/json' -d'{"query":{"range":{"age":{"gt":18}}}}'
```
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