# 使用MySQL客户端连接PolarDB
$ mysql -u fgedu -p -h pc-12345678.mysql.polardb.rds.aliyuncs.com -P 3306
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 12345
Server version: 8.0.29 PolarDB for MySQL 5.7.1

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type ‘help;’ or ‘\h’ for help. Type ‘\c’ to clear the current input statement.

mysql> SELECT version();
+————————-+
| version() |
+————————-+
| 8.0.29 PolarDB for MySQL 5.7.1 |
+————————-+
1 row in set (0.00 sec)

# 使用psql客户端连接PolarDB PostgreSQL
$ psql “host=pc-12345678.pg.polardb.rds.aliyuncs.com port=5432 user=fgedu dbname=fgedudb”
Password for user fgedu:
psql (13.3)
Type “help” for help.

fgedudb=> SELECT version();
version
———————————————————————————————————=
PostgreSQL 11.9 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 7.3.1 20180712 (Red Hat 7.3.1-12), 64-bit
(1 row)

# 使用阿里云CLI管理PolarDB
$ aliyun polardb DescribeDBClusters
{
“DBClusters”: [
{
“DBClusterId”: “pc-12345678”,
“DBClusterDescription”: “fgedu-production-cluster”,
“Engine”: “MySQL”,
“EngineVersion”: “8.0”,
“DBNodeClass”: “polar.mysql.x4.large”,
“Status”: “Running”,
“CreateTime”: “2026-03-31T10:00:00Z”,
“EndTime”: “”,
“DBClusterNetworkType”: “VPC”,
“VPCId”: “vpc-12345678”,
“VSwitchId”: “vsw-12345678”,
“ZoneId”: “cn-hangzhou-a”,
“PayType”: “PostPaid”,
“DBNodeCount”: 1,
“MasterUsername”: “fgedu”,
“Port”: “3306”,
“ConnectionString”: “pc-12345678.mysql.polardb.rds.aliyuncs.com”
}
],
“RequestId”: “12345678-1234-1234-1234-1234567890ab”
}

# 使用DBeaver管理PolarDB
# 步骤1：打开DBeaver
# 步骤2：点击”新建连接”
# 步骤3：选择”MySQL”
# 步骤4：填写连接信息
– 主机：pc-12345678.mysql.polardb.rds.aliyuncs.com
– 端口：3306
– 数据库：fgedudb
– 用户名：fgedu
– 密码：password
# 步骤5：点击”测试连接”
# 步骤6：点击”完成”

# 使用Navicat管理PolarDB
# 步骤1：打开Navicat
# 步骤2：点击”新建连接”
# 步骤3：选择”MySQL”
# 步骤4：填写连接信息
– 连接名：fgedu-polarDB
– 主机：pc-12345678.mysql.polardb.rds.aliyuncs.com
– 端口：3306
– 用户名：fgedu
– 密码：password
# 步骤5：点击”测试连接”
# 步骤6：点击”确定”

# 使用阿里云控制台管理PolarDB
# 步骤1：登录阿里云控制台
# 步骤2：进入PolarDB管理控制台
# 步骤3：选择实例
# 步骤4：查看实例状态
# 步骤5：执行管理操作（如重启、扩容等）

# 连接失败故障排查

# 问题：无法连接到PolarDB实例

# 排查步骤：
1. 检查网络连接
$ ping pc-12345678.mysql.polardb.rds.aliyuncs.com
PING pc-12345678.mysql.polardb.rds.aliyuncs.com (192.168.1.100) 56(84) bytes of data.
64 bytes from 192.168.1.100: icmp_seq=1 ttl=64 time=0.500 ms

2. 检查端口是否开放
$ telnet pc-12345678.mysql.polardb.rds.aliyuncs.com 3306
Trying 192.168.1.100…
Connected to pc-12345678.mysql.polardb.rds.aliyuncs.com.
Escape character is ‘^]’.

3. 检查用户名和密码
$ mysql -u fgedu -p -h pc-12345678.mysql.polardb.rds.aliyuncs.com -P 3306
Enter password:
ERROR 1045 (28000): Access denied for user ‘fgedu’@’192.168.1.200’ (using password: YES)

4. 检查权限
mysql> SHOW GRANTS FOR ‘fgedu’@’%’;
+———————————————————————+
| Grants for fgedu@% |
+———————————————————————+
| GRANT ALL PRIVILEGES ON *.* TO ‘fgedu’@’%’ WITH GRANT OPTION |
+———————————————————————+

5. 检查实例状态
$ aliyun polardb DescribeDBClusters –DBClusterId “pc-12345678”
{
“DBClusters”: [
{
“DBClusterId”: “pc-12345678”,
“Status”: “Running”
}
]
}

# 连接数过多故障排查

# 问题：连接数过多，无法建立新连接

# 排查步骤：
1. 查看当前连接数
mysql> SHOW GLOBAL STATUS LIKE ‘Threads_connected’;
+——————-+——-+
| Variable_name | Value |
+——————-+——-+
| Threads_connected | 1000 |
+——————-+——-+

2. 查看最大连接数
mysql> SHOW VARIABLES LIKE ‘max_connections’;
+—————–+——-+
| Variable_name | Value |
+—————–+——-+
| max_connections | 1000 |
+—————–+——-+

3. 查看连接详情
mysql> SHOW PROCESSLIST;

4. 优化连接池配置
# 调整连接池最大连接数
# 增加实例规格
# 优化应用程序连接管理