Golang MySQL错误-packet.go：33：意外的EOF

Question

I am switching my entire code base from PHP to Go and during several processes that run, I randomly get this error:

[mysql] 2016/10/11 09:17:16 packets.go:33: unexpected EOF

Here is my db package that handles all connections to the database:

package db

import (
    "database/sql"
    _ "github.com/go-sql-driver/mysql"
    "pkg/db"
)

var connection *sql.DB
var err error

func GetConnection() *sql.DB {
    if connection != nil {
        fmt.Println("********** CHECKING PING")
        err = connection.Ping()
        if err == nil {
            fmt.Println("************ CONNECTION STILL ACTIVE")
            return connection
        } else {
            fmt.Println("********** PING ERROR: " + err.Error())
        }
    }

    connection, err = sql.Open("mysql", db.DEVUSER + ":" + db.DEVUSER_PASSWORD + "@tcp(localhost:3306)/main?parseTime=true")
    if err != nil {
        panic(err)
    }

    return connection
}

Is there anything I'm doing wrong with this db package that causes this error to be thrown? What exactly does this error mean? I make sure to return the current connection if there is one open so for multiple requests it uses the same connection object.

Here's an excerpt from the mysql packets.go:

// Read packet to buffer 'data'
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)
            mc.Close()
            return nil, driver.ErrBadConn
        }

        // Packet Length [24 bit]
        pktLen := int(uint32(data[0]) | uint32(data[1])<<8 | uint32(data[2])<<16)

        if pktLen < 1 {
            errLog.Print(ErrMalformPkt)
            mc.Close()
            return nil, driver.ErrBadConn
        }

        // Check Packet Sync [8 bit]
        if data[3] != mc.sequence {
            if data[3] > mc.sequence {
                return nil, ErrPktSyncMul
            }
            return nil, ErrPktSync
        }
        mc.sequence++

        // Read packet body [pktLen bytes]
        data, err = mc.buf.readNext(pktLen)
        if err != nil {
            errLog.Print(err)
            mc.Close()
            return nil, driver.ErrBadConn
        }

        isLastPacket := (pktLen < maxPacketSize)

        // Zero allocations for non-splitting packets
        if isLastPacket && payload == nil {
            return data, nil
        }

        payload = append(payload, data...)

        if isLastPacket {
            return payload, nil
        }
    }
}

The first "errLog.Print(err)" is line 33 in the "Read packet header" section.

Any help is greatly appreciated!

I added a few log.Println to the connection package and let the process run, and right where I get this error, this is what the console prints:

********** CHECKING PING
************ CONNECTION STILL ACTIVE
[mysql] 2016/10/11 11:57:27 packets.go:33: unexpected EOF
********** CHECKING PING
************ CONNECTION STILL ACTIVE

Answer 1

Looks like the link to the github issue provided the fix. The fix, at least for my situation was setting the MaxIdleConnections to 0. I have kept a server up for 24 hours, running queries against it every several hours and have yet to reproduce the error.

Thanks to @city for the link.