1.先检查代码是否及时关闭了MySQL的连接，或者是开启的连接池太大
MySQL默认的连接个数是151:
mysql> show variables like 'max_connections' \G
*************************** 1. row ***************************
Variable_name: max_connections
Value: 151
1 row in set (0.00 sec)
2.如果需要改变打开个数可以修改my.cnf将
max_connections = XXX
改成需要的个数。
或者通过mysql client改变,用root角色进入MySQL:
mysql> set global max_connections=5000;
Query OK, 0 rows affected (0.00 sec)
mysql> show variables like 'max_connections' \G
*************************** 1. row ***************************
Variable_name: max_connections
Value: 5000
1 row in set (0.00 sec)
