最近由于某某漏洞原因,2000万开房数据被曝光,数据是csv格式,打开慢的要死,于是想把这2000w的开房数据导入mysql,然后用go写个简单的查询工具。
悲剧开始了:
第一步,下载 mysql模块,go get github.com/go-sql-driver/mysql,
第二步,写个小例子测试下
package main import ( "database/sql" //这包一定要引用 "encoding/json" "fmt" //这个前面一章讲过 _ "github.com/go-sql-driver/mysql" //这就是刚才下载的包 ) // 定义一个结构体, 需要大写开头哦, 字段名也需要大写开头哦, 否则json模块会识别不了 // 结构体成员仅大写开头外界才能访问 type User struct { User string `json:"user"` Password string `json:"password"` Host string `json:"host"` } // 一如既往的main方法 func main() { // 格式有点怪, @tcp 是指网络协议(难道支持udp?), 然后是域名和端口 db, e := sql.Open("mysql", "root:@tcp(192.168.7.15:3306)/mysql?charset=utf8") if e != nil { //如果连接出错,e将不是nil的 print("ERROR?") return } defer db.Close() // 提醒一句, 运行到这里, 并不代表数据库连接是完全OK的, 因为发送第一条SQL才会校验密码 汗~! rows, e := db.Query("select user,password,host from mysql.user") if e != nil { fmt.Printf("query error!!%v\n", e) return } if rows == nil { print("Rows is nil") return } fmt.Println("DB rows.Next") for rows.Next() { //跟java的ResultSet一样,需要先next读取 user := new(User) // rows貌似只支持Scan方法 继续汗~! 当然,可以通过GetColumns()来得到字段顺序 row_err := rows.Scan(&user.User, &user.Password, &user.Host) if row_err != nil { print("Row error!!") return } b, _ := json.Marshal(user) fmt.Println(string(b)) // 这里没有判断错误, 呵呵, 一般都不会有错吧 } fmt.Println("Done") }
结果一直报错:
panic: runtime error: index out of range goroutine 1 [running]: github.com/go-sql-driver/mysql.readLengthEncodedInteger(0x10fb0037, 0x1, 0xfc9, 0x0, 0x0, ...) E:/go/src/github.com/go-sql-driver/mysql/utils.go:406 +0x3e8 github.com/go-sql-driver/mysql.skipLengthEnodedString(0x10fb0037, 0x1, 0xfc9, 0x2, 0x0, ...) E:/go/src/github.com/go-sql-driver/mysql/utils.go:366 +0x38 github.com/go-sql-driver/mysql.(*mysqlConn).readColumns(0x10f88230, 0x1, 0x10f86500, 0x1, 0x1, ...) E:/go/src/github.com/go-sql-driver/mysql/packets.go:482 +0x389 github.com/go-sql-driver/mysql.(*mysqlConn).getSystemVar(0x10f88230, 0x530b88, 0x12, 0x0, 0x0, ...) E:/go/src/github.com/go-sql-driver/mysql/connection.go:228 +0x118 github.com/go-sql-driver/mysql.(*mysqlDriver).Open(0x5f0bf4, 0x547aa8, 0x2f, 0x1, 0x10f9f900, ...) E:/go/src/github.com/go-sql-driver/mysql/driver.go:70 +0x2de database/sql.(*DB).conn(0x10f85e40, 0x10f50228, 0xff014c, 0x5) C:/Users/ADMINI~1/AppData/Local/Temp/2/bindist465310315/go/src/pkg/database/sql/sql.go:484 +0x15e database/sql.(*DB).query(0x10f85e40, 0x527b68, 0x8, 0x0, 0x0, ...) C:/Users/ADMINI~1/AppData/Local/Temp/2/bindist465310315/go/src/pkg/database/sql/sql.go:708 +0x58 database/sql.(*DB).Query(0x10f85e40, 0x527b68, 0x8, 0x0, 0x0, ...) C:/Users/ADMINI~1/AppData/Local/Temp/2/bindist465310315/go/src/pkg/database/sql/sql.go:699 +0x6b main.main() E:/go/src/testmysql/testmysql.go:54 +0x89 goroutine 3 [syscall]: syscall.Syscall6(0x7c80a7bd, 0x5, 0xf70, 0x10f86420, 0x10f50280, ...) C:/Users/ADMINI~1/AppData/Local/Temp/2/bindist465310315/go/src/pkg/runtime/zsyscall_windows_windows_386.c:97 +0x49 syscall.GetQueuedCompletionStatus(0xf70, 0x10f86420, 0x10f50280, 0x10f50278, 0xffffffff, ...) C:/Users/ADMINI~1/AppData/Local/Temp/2/bindist465310315/go/src/pkg/syscall/zsyscall_windows_386.go:507 +0x7e net.(*resultSrv).Run(0x10f50260) C:/Users/ADMINI~1/AppData/Local/Temp/2/bindist465310315/go/src/pkg/net/fd_windows.go:150 +0x11a created by net.startServer C:/Users/ADMINI~1/AppData/Local/Temp/2/bindist465310315/go/src/pkg/net/fd_windows.go:285 +0xde goroutine 4 [select]: net.(*ioSrv).ProcessRemoteIO(0x10f50268) C:/Users/ADMINI~1/AppData/Local/Temp/2/bindist465310315/go/src/pkg/net/fd_windows.go:183 +0x171 created by net.startServer C:/Users/ADMINI~1/AppData/Local/Temp/2/bindist465310315/go/src/pkg/net/fd_windows.go:293 +0x163 exit status 2
刚开始怀疑windows没有装mysql驱动,可是兴趣来了想分析下堆栈信息,正好学点新东西,
log大法,跟踪readLengthEncodedInteger,并加入如下调试代码,打印b[]byte的内存信息,发现b[0] = 0xfe,但是后面却没有数据了,所以造成了数组b的index溢出,完整代码如下:
func readLengthEncodedInteger(b []byte) (num uint64, isNull bool, n int) { fmt.Println(b) fmt.Printf("0x%02x\n", b[0]) switch b[0] { // 251: NULL case 0xfb: n = 1 isNull = true return // 252: value of following 2 case 0xfc: num = uint64(b[1]) | uint64(b[2])<<8 n = 3 return // 253: value of following 3 case 0xfd: num = uint64(b[1]) | uint64(b[2])<<8 | uint64(b[3])<<16 n = 4 return // 254: value of following 8 case 0xfe: num = uint64(b[1]) | uint64(b[2])<<8 | uint64(b[3])<<16 | uint64(b[4])<<24 | uint64(b[5])<<32 | uint64(b[6])<<40 | uint64(b[7])<<48 | uint64(b[8])<<54 n = 9 return } // 0-250: value of first byte num = uint64(b[0]) n = 1 return }
继续跟踪发现:package.go的readColumns中有一个很奇怪的退出,但是没有这个0xfe的处理,而且奇怪的是for循环只有这里可以正常return。。。
func (mc *mysqlConn) readColumns(count int) (columns []mysqlField, err error) { var data []byte var i, pos, n int var name []byte columns = make([]mysqlField, count) fmt.Println("count:") fmt.Println(count) for { data, err = mc.readPacket() if err != nil { return } // EOF Packet if data[0] == iEOF && len(data) == 5 { if i != count { err = fmt.Errorf("ColumnsCount mismatch n:%d len:%d", count, len(columns)) } return }
发现重要说明,这个Column的包后面有一个EOF_Packet,也就是上面的0xfe,于是怀疑这是go mysql driver的一个bug
15.6.5.1. COM_FIELD_LIST response
The response to a COM_FIELD_LIST can either be a
a ERR_Packet or
one or more Column Definition packets and a closing EOF_Packet
于是到go-sql-driver的官网 https://github.com/go-sql-driver/mysql/blob/master/packets.go,想pull->提交这个bug的patch,结果。。。
我擦!!这个issue已经在github上修改了,如下:
// EOF Packet if data[0] == iEOF && (len(data) == 5 || len(data) == 1) { if i == count { return columns, nil } return nil, fmt.Errorf("ColumnsCount mismatch n:%d len:%d", count, len(columns)) }
顿时崩溃啊,猜想go get下来的代码是旧版本的,看README.md
**Current tagged Release:** June 03, 2013 (Version 1.0.1)
再看github上
**Current tagged Release:** May 14, 2013 (Version 1.0)
疑问来了,虽然github库上的release版本还是旧的,但是go get下来的新版本存在这个问题!!!???
解决方案:唯一的方式就是取一个github上的版本git clone https://github.com/go-sql-driver/mysql.git,不要用go get的版本。
最后,哪位大神解释下 go get和git clone下来的版本为什么不一样??
补充:
1.@ASTA谢:
因为你之前安装过github.com/go-sql-driver/mysql,所以你go get的时候不会更新,你必须使用go get -u更新,而git clone是最新版本的更新(2013-10-24
16:23:57),这个go get -u 是更新,但不是问题所在,@jimmykuu:默认是去获取tag为go1的代码,果然如jimmykuu所说:我查看tag为go1的代码:https://github.com/go-sql-driver/mysql/tree/go1,和go
get下来的相同,而且golang上有说明。。。"When checking out or updating a package, get looks for a branch or tag that matches the locally installed version of Go. The most important rule
is that if the local installation is running version "go1", get searches for a branch or tag named "go1". If no such version exists it retrieves the most recent version of the package."
所以我的结论就是go-sql-driver中的go1 tag充满bug,不负责任!
2. 刚才看了下,之所以其他人没有碰到这个问题,是因为我正好用的古老版本mysql4.1 ,补丁在这fix crash when connect to mysql4.1:https://github.com/go-sql-driver/mysql/commit/4a178617b97609ebd4d4a0ae5791225540c1bb26#diff-2357b8494bbd2f27c09e61fc8ef5f092
3.用git clone的新版本替换后,切记删掉pkg下生成的mysql.a文件!!
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