### 参考链接
* https://docs.influxdata.com/influxdb/v1.8/introduction/install/
* https://docs.influxdata.com/influxdb/v1.8/introduction/getting-started/
* [Spring Boot中使用时序数据库InfluxDB](http://www.manongjc.com/detail/60-zdzcqmqvsacgbql.html)

### 1、安装InfluxDB
参考链接

 * https://docs.influxdata.com/influxdb/v1.8/introduction/install/
 * [InfluxData TICK栈 1.X 在Windows下安装笔记](https://blog.csdn.net/m0_55628112/article/details/114238785)

#### 1.1 CentOS安装InfluxDB

* 更新配置文件：

```shell
cat <<EOF | sudo tee /etc/yum.repos.d/influxdb.repo
[influxdb]
name = InfluxDB Repository - RHEL \$releasever
baseurl = https://repos.influxdata.com/rhel/\$releasever/\$basearch/stable
enabled = 1
gpgcheck = 1
gpgkey = https://repos.influxdata.com/influxdata-archive_compat.key
EOF
```

* 安装

```shell
sudo yum install influxdb
sudo systemctl enable influxdb
sudo systemctl start influxdb
```

* 配置
 1) Create at least one admin

```shell
CREATE USER admin WITH PASSWORD 'root' WITH ALL PRIVILEGES
```
 2) Enable authentication in your configuration file by setting the auth-enabled option to true in the [http] section:

```ini
[http]
  enabled = true
  bind-address = ":8086"
  auth-enabled = true # Set to true
  log-enabled = true
  write-tracing = false
  pprof-enabled = true
  pprof-auth-enabled = true
  debug-pprof-enabled = false
  ping-auth-enabled = true
  https-enabled = true
  https-certificate = "/etc/ssl/influxdb.pem"
```

  3. Restart InfluxDB.

### 2. 常用命令

#### 2.1 用户管理
```shell
# Create admin user
CREATE USER admin WITH PASSWORD '<password>' WITH ALL PRIVILEGES

# GRANT administrative privileges to an existing user
GRANT ALL PRIVILEGES TO <username>

# REVOKE administrative privileges from an admin user
REVOKE ALL PRIVILEGES FROM <username>

# SHOW all existing users and their admin status
SHOW USERS

# CREATE a new non-admin user
CREATE USER <username> WITH PASSWORD '<password>'

# GRANT READ, WRITE or ALL database privileges to an existing user
GRANT [READ,WRITE,ALL] ON <database_name> TO <username>

# REVOKE READ, WRITE, or ALL database privileges from an existing user
REVOKE [READ,WRITE,ALL] ON <database_name> FROM <username>

# SHOW GRANTS FOR <user_name>
SHOW GRANTS FOR <user_name>

# Reset a user’s password
SET PASSWORD FOR <username> = '<password>'

# DROP a user
DROP USER <username>
```
#### 2.2 数据库相关
```shell
CREATE DATABASE mydb
SHOW DATABASES
USE mydb
SHOW MEASUREMENTS

# 查看InfluxDB中的保留策略
SHOW RETENTION POLICIES ON <database_name>

# 删除InfluxDB中的保留策略
DROP RETENTION POLICY "<policy_name>" ON "<database_name>"

# 查看表结构
show field keys from measurement;
show tag keys from measurement;
```


### 3. springboot集成步骤

#### 3.1 添加Maven依赖
```xml
		<dependency>
			<groupId>org.influxdb</groupId>
			<artifactId>influxdb-java</artifactId>
		</dependency>
```

注意：这里因为Spring Boot 2.x版本的parent中有维护InfluxDB的SDK版本，所以不需要手工指明版本信息。

#### 3.2 配置influxdb连接信息

```yaml
spring:
  influx:
    url: http://127.0.0.1:8086
    user: admin
    password: root
```



#### 3.3 增加保留策略
##### 3.3.1 MQTT日志保留一年
要将MQTT日志数据保存为1年，可以使用以下步骤：

1. 首先，需要在InfluxDB中创建一个新的保留策略。可以使用以下命令在InfluxDB的CLI中创建一个名为"one_year"的保留策略：

```
CREATE RETENTION POLICY "one_year" ON "gas_alarm" DURATION 55w REPLICATION 1 DEFAULT
```

这将在"gas_alarm"的measurement上创建一个名为"one_year"的保留策略，保留时间为1年。

2. 然后，在写入数据时，将保留策略设置为"one_year"。可以使用以下代码将数据写入到"gas_alarm" measurement中，并将保留策略设置为"one_year"：

```
influxDB.write("gas_alarm", "one_year", point);
```

这样，数据将以"one_year"保留策略保存在InfluxDB中，并且会在1年后被自动删除。