我编写了以下ETL工具，它从Mysql获取数据，转换为JSON＆amp;将其打印在屏幕上
package main
import (
"bytes"
"database/sql"
"encoding/json"
"fmt"
"log"
"strconv"
"strings"
"time"
_ "github.com/go-sql-driver/mysql"
)
const dbformat = "2006-01-02 15:04:05"
type MysqlReceipt struct {
Id int
Amount sql.NullFloat64
Cc_last4 sql.NullString
Employee_id sql.NullString
Employee_name sql.NullString
Is_test byte
Menu_items sql.NullString
Payable sql.NullFloat64
Pos_type sql.NullString
Pos_version sql.NullString
Punchh_key string
Receipt_datetime sql.NullString
Subtotal_amount sql.NullFloat64
Transaction_no sql.NullString
Business_id int
Location_id int
Created_at string
Updated_at sql.NullString
Revenue_code sql.NullString
Revenue_id sql.NullString
Status sql.NullString
Ipv4_addr sql.NullString
}
type Menu_item struct {
id, name, family, major_group, item_type string
qty int
amount float64
}
type BigReceipt struct {
Id int
Amount float64
Cc_last4 string
Employee_id string `json:",omitempty"`
Employee_name string `json:",omitempty"`
Is_test byte
Menu_item_name string
Menu_item_id string
Menu_item_amount float64
Menu_item_family string
Menu_item_major_group string
Menu_item_type string
Menu_item_qty int
Payable float64
Pos_type string `json:",omitempty"`
Pos_version string `json:",omitempty"`
Punchh_key string
Receipt_datetime string
Subtotal_amount float64
Transaction_no string `json:",omitempty"`
Business_id, Location_id int
Created_at time.Time
Updated_at time.Time `json:",omitempty"`
Revenue_code string `json:",omitempty"`
Revenue_id string `json:",omitempty"`
Status string `json:",omitempty"`
Ipv4_addr string `json:",omitempty"`
Stored_at int64
}
func (m Menu_item) ValidItem() bool {
if m.item_type == "M" || m.item_type == "D" {
return true
} else {
return false
}
}
func main() {
db, err := sql.Open("mysql", "root:password@tcp(xxxxxxx.us-east-1.rds.amazonaws.com:3306)/db_name_goes_here")
if err != nil {
log.Fatal(err)
}
err = db.Ping()
if err != nil {
log.Fatal(err)
}
defer db.Close()
rows, err := db.Query(`select id,amount,cc_last4,employee_id,employee_name,is_test,menu_items,payable,pos_type,
pos_version,punchh_key,receipt_datetime,subtotal_amount,transaction_no,business_id,location_id,created_at,
updated_at,revenue_code,revenue_id,status,ipv4_addr from receipts`)
if err != nil {
log.Fatal(err)
}
defer rows.Close()
for rows.Next() {
var mr MysqlReceipt
err = rows.Scan(&mr.Id, &mr.Amount, &mr.Cc_last4, &mr.Employee_id, &mr.Employee_name, &mr.Is_test, &mr.Menu_items,
&mr.Payable, &mr.Pos_type, &mr.Pos_version, &mr.Punchh_key, &mr.Receipt_datetime, &mr.Subtotal_amount, &mr.Transaction_no,
&mr.Business_id, &mr.Location_id, &mr.Created_at, &mr.Updated_at, &mr.Revenue_code, &mr.Revenue_id, &mr.Status, &mr.Ipv4_addr)
if err != nil {
log.Fatal(err)
}
if !mr.Menu_items.Valid {
continue
}
r := BigReceipt{Id: mr.Id,
Amount: mr.Amount.Float64,
Cc_last4: mr.Cc_last4.String,
Employee_id: mr.Employee_id.String,
Employee_name: mr.Employee_name.String,
Is_test: mr.Is_test,
Payable: mr.Payable.Float64,
Pos_type: mr.Pos_type.String,
Pos_version: mr.Pos_version.String,
Punchh_key: mr.Punchh_key,
Receipt_datetime: mr.Receipt_datetime.String,
Subtotal_amount: mr.Subtotal_amount.Float64,
Transaction_no: mr.Transaction_no.String,
Business_id: mr.Business_id,
Location_id: mr.Location_id,
Revenue_code: mr.Revenue_code.String,
Revenue_id: mr.Revenue_id.String,
Status: mr.Status.String,
Ipv4_addr: mr.Ipv4_addr.String,
Stored_at: time.Now().Unix(),
}
r.Created_at = datetimeParse(mr.Created_at)
if mr.Updated_at.Valid {
r.Updated_at = datetimeParse(mr.Updated_at.String)
}
menuItems := strings.Split(mr.Menu_items.String, "^")
items := parseMenuItems(menuItems)
for _, v := range items {
r.Menu_item_name = v.name
r.Menu_item_id = v.id
r.Menu_item_amount = v.amount
r.Menu_item_family = v.family
r.Menu_item_major_group = v.major_group
r.Menu_item_type = v.item_type
r.Menu_item_qty = v.qty
b, err := json.Marshal(r)
if err != nil {
log.Fatal(err)
}
fmt.Println(r.Id)
var out bytes.Buffer
json.Compact(&out, b)
fmt.Println(string(b))
}
}
err = rows.Err()
if err != nil {
log.Fatal(err)
}
}
func datetimeParse(dateStr string) time.Time {
datetime, err := time.Parse(dbformat, dateStr)
if err != nil {
log.Fatal(err)
}
return datetime
}
func parseMenuItems(menuItems []string) []Menu_item {
var items []Menu_item
var item Menu_item
for _, v := range menuItems {
itemParts := strings.Split(v, "|")
item.name = itemParts[0]
item.qty, _ = strconv.Atoi(itemParts[1])
item.amount, _ = strconv.ParseFloat(itemParts[2], 64)
item.item_type = strings.ToUpper(itemParts[3])
item.id = itemParts[4]
item.family = itemParts[5]
item.major_group = itemParts[6]
if item.ValidItem() {
items = append(items, item)
} else {
continue
}
}
return items
}
现在，这适用于测试数据库，但在生产数据库中有数百万行，它在获取1,000行后会卡住。停止在屏幕上打印。我让它跑了一夜。
早上，
我发了QUIT信号＆amp;获得了以下堆栈跟踪
SIGQUIT: quit
PC=0x5fecb m=0
goroutine 0 [idle]:
runtime.mach_semaphore_wait(0xe03, 0x0, 0x0, 0x0, 0x0, 0x407520, 0x52db9, 0xffffffffffffffff, 0x0, 0x7fff5fbff0fc, ...)
/usr/local/Cellar/go/1.5/libexec/src/runtime/sys_darwin_amd64.s:407 +0xb
runtime.semasleep1(0xffffffffffffffff, 0x0)
/usr/local/Cellar/go/1.5/libexec/src/runtime/os1_darwin.go:385 +0xe5
runtime.semasleep.func1()
/usr/local/Cellar/go/1.5/libexec/src/runtime/os1_darwin.go:401 +0x29
runtime.systemstack(0x7fff5fbff100)
/usr/local/Cellar/go/1.5/libexec/src/runtime/asm_amd64.s:278 +0xab
runtime.semasleep(0xffffffffffffffff, 0x0)
/usr/local/Cellar/go/1.5/libexec/src/runtime/os1_darwin.go:402 +0x36
runtime.notesleep(0x407970)
/usr/local/Cellar/go/1.5/libexec/src/runtime/lock_sema.go:169 +0x100
runtime.stopm()
/usr/local/Cellar/go/1.5/libexec/src/runtime/proc1.go:1128 +0x112
runtime.findrunnable(0xc82001d500, 0x0)
/usr/local/Cellar/go/1.5/libexec/src/runtime/proc1.go:1530 +0x69e
runtime.schedule()
/usr/local/Cellar/go/1.5/libexec/src/runtime/proc1.go:1639 +0x267
runtime.park_m(0xc820000180)
/usr/local/Cellar/go/1.5/libexec/src/runtime/proc1.go:1698 +0x18b
runtime.mcall(0x7fff5fbff280)
/usr/local/Cellar/go/1.5/libexec/src/runtime/asm_amd64.s:204 +0x5b
goroutine 1 [IO wait]:
net.runtime_pollWait(0x7a1000, 0x72, 0xc82000a2d0)
/usr/local/Cellar/go/1.5/libexec/src/runtime/netpoll.go:157 +0x60
net.(*pollDesc).Wait(0xc8200a4060, 0x72, 0x0, 0x0)
/usr/local/Cellar/go/1.5/libexec/src/net/fd_poll_runtime.go:73 +0x3a
net.(*pollDesc).WaitRead(0xc8200a4060, 0x0, 0x0)
/usr/local/Cellar/go/1.5/libexec/src/net/fd_poll_runtime.go:78 +0x36
net.(*netFD).Read(0xc8200a4000, 0xc820372077, 0x3f89, 0x3f89, 0x0, 0x760050, 0xc82000a2d0)
/usr/local/Cellar/go/1.5/libexec/src/net/fd_unix.go:232 +0x23a
net.(*conn).Read(0xc8200a6000, 0xc820372077, 0x3f89, 0x3f89, 0x0, 0x0, 0x0)
/usr/local/Cellar/go/1.5/libexec/src/net/net.go:172 +0xe4
github.com/go-sql-driver/mysql.(*buffer).fill(0xc820080080, 0x102, 0x0, 0x0)
/Users/gaurish/golang/src/github.com/go-sql-driver/mysql/buffer.go:57 +0x2b5
github.com/go-sql-driver/mysql.(*buffer).readNext(0xc820080080, 0x102, 0x0, 0x0, 0x0, 0x0, 0x0)
/Users/gaurish/golang/src/github.com/go-sql-driver/mysql/buffer.go:86 +0x55
github.com/go-sql-driver/mysql.(*mysqlConn).readPacket(0xc820080080, 0x0, 0x0, 0x0, 0x0, 0x0)
/Users/gaurish/golang/src/github.com/go-sql-driver/mysql/packets.go:57 +0x47a
github.com/go-sql-driver/mysql.(*mysqlConn).readUntilEOF(0xc820080080, 0x0, 0x0)
/Users/gaurish/golang/src/github.com/go-sql-driver/mysql/packets.go:698 +0x2d
github.com/go-sql-driver/mysql.(*mysqlRows).Close(0xc8200a0120, 0x0, 0x0)
/Users/gaurish/golang/src/github.com/go-sql-driver/mysql/rows.go:67 +0x73
database/sql.(*Rows).Close(0xc8200aa060, 0x0, 0x0)
/usr/local/Cellar/go/1.5/libexec/src/database/sql/sql.go:1710 +0x92
main.parseMenuItems(0xc82036e480, 0x44, 0x44, 0x0, 0x0, 0x0)
/Users/gaurish/code/practice/mysql2json/mysql2json.go:186 +0x468
main.main()
/Users/gaurish/code/practice/mysql2json/mysql2json.go:142 +0xf2e
goroutine 17 [syscall, locked to thread]:
runtime.goexit()
/usr/local/Cellar/go/1.5/libexec/src/runtime/asm_amd64.s:1696 +0x1
goroutine 5 [chan receive]:
database/sql.(*DB).connectionOpener(0xc820088960)
/usr/local/Cellar/go/1.5/libexec/src/database/sql/sql.go:634 +0x45
created by database/sql.Open
/usr/local/Cellar/go/1.5/libexec/src/database/sql/sql.go:481 +0x336
rax 0xe
rbx 0xe03
rcx 0x7fff5fbff088
rdx 0x7fff5fbff100
rdi 0xe03
rsi 0x407520
rbp 0x407860
rsp 0x7fff5fbff088
r8 0x407860
r9 0x0
r10 0x0
r11 0x286
r12 0x2c
r13 0x4fc3ed4b8b0
r14 0x14059837c8b46200
r15 0x38
rip 0x5fecb
rflags 0x286
cs 0x7
fs 0x0
gs 0x0
exit status 2
此外，我尝试通过评论defer rows.Close()来进一步调试它。现在经过1,000行左右，而不是停滞，它立即返回以下错误：
panic: runtime error: index out of range
goroutine 1 [running]:
main.parseMenuItems(0xc820366900, 0x44, 0x44, 0x0, 0x0, 0x0)
/Users/gaurish/code/practice/mysql2json/mysql2json.go:186 +0x468
main.main()
/Users/gaurish/code/practice/mysql2json/mysql2json.go:142 +0xf03
goroutine 17 [syscall, locked to thread]:
runtime.goexit()
/usr/local/Cellar/go/1.5/libexec/src/runtime/asm_amd64.s:1696 +0x1
goroutine 5 [runnable]:
database/sql.(*DB).connectionOpener(0xc820088780)
/usr/local/Cellar/go/1.5/libexec/src/database/sql/sql.go:634 +0x45
created by database/sql.Open
/usr/local/Cellar/go/1.5/libexec/src/database/sql/sql.go:481 +0x336
exit status 2
问题：
defer rows.Close()如何停止卡住＆amp;恐慌吗？ 最后，如果上述任何一个是愚蠢的问题或问题太长，我很抱歉。我是Go＆amp; S的新手试着学习。
答案 0 :(得分：0)
这是驱动程序的问题。通过删除延迟通话和放大来修复它检查数组边界。