golang mysql bad connection - mysql

Question

$ wrk -c300 -d10m -t8 url
SetMaxOpenConns(100)
When wrk just started, Occasional bad connection error, And the number of mysql PROCESSLIST is less than 100, around 70
I modified the file
database/sql/sql.go
func OpenDB(c driver.Connector) *DB {
ctx, cancel := context.WithCancel(context.Background())
db := &DB{
connector: c,
openerCh: make(chan struct{}, connectionRequestQueueSize),
resetterCh: make(chan *driverConn, 50),
lastPut: make(map[*driverConn]string),
connRequests: make(map[uint64]chan connRequest),
stop: cancel,
}
go db.connectionOpener(ctx)
go db.connectionResetter(ctx)
return db
}
Changed the buffer length of resetterCh
resetterCh: make(chan *driverConn, 100),
Solved the bad connection problem, and the number of mysql PROCESSLIST instantly reached 100
Is there a problem with my solution?
minimal reproducible example
package main
import (
"fmt"
"github.com/jinzhu/gorm"
"net/http"
_ "github.com/go-sql-driver/mysql"
//_ "github.com/jinzhu/gorm/dialects/mysql"
"time"
)
var (
MysqlClient *gorm.DB
)
const (
user = ""
pwd = ""
host = ""
port = ""
dbname = ""
)
func main() {
initMysqlDb()
http.HandleFunc("/", ActionHandler)
http.ListenAndServe(":18001", nil)
}
type Reguserinfo struct {
Rid int `gorm:"primary_key;column:rid;type:int(10) unsigned;not null" json:"rid"`
Username string `gorm:"unique;column:username;type:varchar(64);not null" json:"username"`
}
func initMysqlDb() {
var err error
uri := fmt.Sprintf("%s:%s#tcp(%s:%s)/%s?charset=utf8mb4&parseTime=True&loc=Local&interpolateParams=true",
user, pwd, host, port, dbname)
MysqlClient, err = gorm.Open("mysql", uri)
if err != nil {
fmt.Println("mysql open err", err)
return
}
// SetMaxIdleConns sets the maximum number of connections in the idle connection pool.
MysqlClient.DB().SetMaxIdleConns(10)
// SetMaxOpenConns sets the maximum number of open connections to the database.
MysqlClient.DB().SetMaxOpenConns(100)
// SetConnMaxLifetime sets the maximum amount of time a connection may be reused.
MysqlClient.DB().SetConnMaxLifetime(100 * time.Second)
MysqlClient.LogMode(false)
MysqlClient.SingularTable(true) //表名后默认+s,关闭之
}
func ActionHandler(w http.ResponseWriter, r *http.Request) {
var result *gorm.DB
var registerInfo Reguserinfo
result = MysqlClient.Where("rid = ?", 2).First(&registerInfo)
if result.Error != nil {
fmt.Println("err", result.Error)
}
w.Write([]byte("hello"))
}
shell run wrk -c300 -d10m -t8 http://127.0.0.1:18001/
This example can be reproduced