然后执行一下脚本，检查状态变量Aborted_clients，然后发现状态变量Aborted_clients的值增1了。

2、 客户端休眠的时间超过了系统变量wait_timeout和interactive_timeout的值，导致连接被MySQL进程终止

mysql> show global variables like 'interactive_timeout';
+---------------------+-------+
| Variable_name       | Value |
+---------------------+-------+
| interactive_timeout | 28800 |
+---------------------+-------+
1 row in set (0.00 sec)

mysql> show global variables like 'wait_timeout';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| wait_timeout  | 28800 |
+---------------+-------+
1 row in set (0.00 sec)

mysql>

将全局系统变量interactive_timeout 和wait_timeout设置为4秒

mysql> set global interactive_timeout=4;
Query OK, 0 rows affected (0.00 sec)

mysql> set global wait_timeout=4;
Query OK, 0 rows affected (0.00 sec)

mysql> show status like 'Abort%';
+------------------+-------+
| Variable_name    | Value |
+------------------+-------+
| Aborted_clients  | 0     |
| Aborted_connects | 0     |
+------------------+-------+
2 rows in set (0.00 sec)

然后在客户端连接到MySQL数据库，不做任何操作，过来4秒后，你去操作就会出现错误“ERROR 2013 (HY000): Lost connection to MySQL server during query”

# mysql -h 10.20.57.24 -u test -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 43
Server version: 5.6.20-enterprise-commercial-advanced-log MySQL Enterprise Server - Advanced Edition (Commercial)

Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.

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 current_user();
ERROR 2013 (HY000): Lost connection to MySQL server during query
mysql>

在MySQL服务器你就会看到状态变量Aborted_clients变为1了。

mysql> show status like 'Abort%';

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

| Variable_name    | Value |

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

| Aborted_clients  | 1     |

| Aborted_connects | 0     |

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

2 rows in set (0.00 sec

还有其他一些原因(客户端异常中断或查询超出了max_allowed_packet值)由于不方便构造，在此略过。另外，其实我们还可以通过tcpdump抓包工具来追踪分析。下面举个例子（这里 

简单介绍一下tcpdump,后续文章再做展开分析）

在MySQL服务器使用tcpdump抓包

[root@DB-Server ~]# tcpdump -i eth0 port 3306 -s 1500 -w tcpdump.log

然后在另外一台MySQL服务器，使用不存在的账号或错误的密码访问MySQL数据库

# mysql -h 10.20.57.24 -u kkk -p

Enter password:

ERROR 1045 (28000): Access denied for user 'kkk'@'192.168.7.208' (using password: YES)

# mysql -h 10.20.57.24 -u test -p

Enter password:

ERROR 1045 (28000): Access denied for user 'test'@'192.168.7.208' (using password: YES)

[root@GETLNX28 ~]#

执行完命令后，你可以使用CTRL + C结束抓包分析，然后查看分析。如下截图所示：

[root@DB-Server ~]# tcpdump -i eth0 port 3306 -s 1500 -w tcpdump.log

tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 1500 bytes

28 packets captured

28 packets received by filter

0 packets dropped by kernel

[root@DB-Server ~]# strings tcpdump.log

参考资料：