使用go-sql-driver.mysql包报错unexpected EOF

使用go-sql-driver/mysql包报错，信息以下：

[mysql] 2016/12/29 12:05:34 packets.go:33: unexpected EOF
[mysql] 2016/12/29 12:05:34 packets.go:124: write tcp 10.94.104.39:42418->10.94.104.39:3306: write: broken pipe

下面是输出错误信息的代码：

func (mc *mysqlConn) readPacket() ([]byte, error) {
	var payload []byte
	for {
		// Read packet header
		data, err := mc.buf.readNext(4)
		if err != nil {
			errLog.Print(err)//在此处输出错误
			mc.Close()
			return nil, driver.ErrBadConn
		}
        ·······
	}
}

在errLog.Print(err)下面加一行panic(err)，就能够知道是哪调用的readPacket()，并在mc.buf.readNext(4)这一行下面添加errLog.Print("readPacket:", data, err)，观察下输出的数据; 下面是panic信息：

[mysql] 2016/12/29 15:08:16 packets.go:32: readPacket:[] unexpected EOF
[mysql] 2016/12/29 15:08:16 packets.go:34: unexpected EOF
panic: unexpected EOF

goroutine 16 [running]:
panic(0x877700, 0xc82000a180)
	/home/project/go/src/runtime/panic.go:481 +0x3e6
github.com/go-sql-driver/mysql.(*mysqlConn).readPacket(0xc820082870, 0x0, 0x0, 0x0, 0x0, 0x0)
	/home/project/webroot/test/src/github.com/go-sql-driver/mysql/packets.go:35 +0x384
github.com/go-sql-driver/mysql.(*mysqlStmt).readPrepareResultPacket(0xc820104e10, 0xc820104e10, 0x0, 0x0)
	/home/project/webroot/test/src/github.com/go-sql-driver/mysql/packets.go:757 +0x48
github.com/go-sql-driver/mysql.(*mysqlConn).Prepare(0xc820082870, 0xc820082990, 0x85, 0x0, 0x0, 0x0, 0x0)
	/home/project/webroot/test/src/github.com/go-sql-driver/mysql/connection.go:121 +0x21f
database/sql.(*DB).queryConn(0xc8200c22c0, 0xc82005ae70, 0xc82010cc70, 0xc820082990, 0x85, 0xc8201091c0, 0x4, 0x4, 0xc820082990, 0x0, ...)
	/home/project/go/src/database/sql/sql.go:1110 +0x31a
database/sql.(*DB).query(0xc8200c22c0, 0xc820082990, 0x85, 0xc8201091c0, 0x4, 0x4, 0x224b1b01, 0x4c1328, 0x0, 0x0)
	/home/project/go/src/database/sql/sql.go:1078 +0x126
database/sql.(*DB).Query(0xc8200c22c0, 0xc820082990, 0x85, 0xc8201091c0, 0x4, 0x4, 0x0, 0x0, 0x0)
	/home/project/go/src/database/sql/sql.go:1061 +0xa3
models.TestDbQuery(0xc820082990, 0x85, 0xc8201091c0, 0x4, 0x4, 0x0, 0x0, 0x0)
	/home/project/webroot/test/src/models/db_test.go:77 +0xb5
models.GetSomeTasks(0x0, 0x0, 0x0, 0x0, 0x0)
	/home/project/webroot/test/src/models/tasks.go:46 +0x2e1
logic.ScanTasks(0xc820100a60, 0xc8200649c0)
	/home/project/webroot/test/src/logic/group.go:23 +0x84
created by main.main
	/home/project/webroot/test/src/main.go:87 +0x3e5

按着上面显示的方法，逐个查看也并未发现有什么错误。

既然代码这方面没有什么明显错误，那就查看下mysql server端，查看设置的超时时间：

mysql> show variables like "%timeout%";
+----------------------------+----------+
| Variable_name              | Value    |
+----------------------------+----------+
| connect_timeout            | 10       |
| delayed_insert_timeout     | 300      |
| innodb_lock_wait_timeout   | 50       |
| innodb_rollback_on_timeout | OFF      |
| interactive_timeout        | 600      |
| lock_wait_timeout          | 31536000 |
| net_read_timeout           | 30       |
| net_write_timeout          | 60       |
| slave_net_timeout          | 3600     |
| wait_timeout               | 600      |
+----------------------------+----------+
10 rows in set (0.01 sec)

interactive_timeout和wait_timeout都是600，在短短几秒内不会断开链接，百思不得其解啊，最后查看下my.cnf，发现interactive_timeout和wait_timeout这两个的值是5，到此明了了，果真是链接的问题，以前显示600是由于多天前作实验设置为600了，可是这个只是对当前session有效，实际程序中的时间仍是5sec。

注意：作完实验后及时改回配置文件。