最近在用mysql的时候，双击表突然出现1040 too many connection的错误，看错误的意思是连接的人数太多了。

当最大连接数比较小时，可能会出现“1040 too many connection”错误。

1、首先需要重启MySQL服务，执行命令：

[root@iZ23 ~]# service mysql restart

或者：

[root@iZ23 ~]# service mysqld restart

2、登录mysql，

[root@iZ23 ~]# mysql -uroot -p

输入密码，回车；

3、登录成功后执行以下语句查询当前的最大连接数：

mysql> select VARIABLE_VALUE from information_schema.GLOBAL_VARIABLES where VARIABLE_NAME='MAX_CONNECTIONS';

+----------------+

| VARIABLE_VALUE |

+----------------+

| 151            |

+----------------+

1 row in set (0.00 sec)

4、执行以下语句修改最大连接数：

mysql> set global max_connections = 3600;

Query OK, 0 rows affected (0.00 sec)

好了，再打开表就不会报错了

补充：升级5.7后报错

mysql> select VARIABLE_VALUE from information_schema.GLOBAL_VARIABLES where VARIABLE_NAME='MAX_CONNECTIONS';

ERROR 3167 (HY000): The 'INFORMATION_SCHEMA.GLOBAL_VARIABLES' feature is disabled; see the documentation for 'show_compatibility_56'

mysql>

mysql>  show variables like '%show_compatibility_56%';

+-----------------------+-------+

| Variable_name         | Value |

+-----------------------+-------+

| show_compatibility_56 | OFF   |

+-----------------------+-------+

1 row in set (0.00 sec)

mysql>

mysql>  set global show_compatibility_56=on;

Query OK, 0 rows affected (0.00 sec)

mysql> show variables like '%show_compatibility_56%';

+-----------------------+-------+

| Variable_name         | Value |

+-----------------------+-------+

| show_compatibility_56 | ON    |

+-----------------------+-------+

1 row in set (0.00 sec)

mysql>

mysql> select * from information_schema.global_status limit 3;