go 協程批量查詢數據庫

go 協程批量查詢數據庫

func init() {
	dsn := fmt.Sprintf("%s:%s@%s(%s:%d)/%s", USERNAME, PASSWORD, NETWORK, SERVER, PORT, DATABASE)
	NEWDB, err = sql.Open("mysql", dsn)
	if err != nil {
		fmt.Printf("Open mysql failed,err:%v\n", err)
		return
	}
	//DB.SetConnMaxLifetime(1 * time.Second) //最大連接週期，超過時間的連接就close
	NEWDB.SetMaxOpenConns(8) //設置最大連接數
	NEWDB.SetMaxIdleConns(5) //設置閒置連接數
	fmt.Printf("數據庫連接池準備成功")
}


func process() {
	//DB := NEWDB
	//4個攜程，4個查詢連接，還要寫入，最少8個連接數
	total := 100
	process := 4
	pageSize := 10
	eachTimes := total / process //沒給攜程處理的條數
	for i := 0; i < process; i++ {
		startId := i * eachTimes
		endId := eachTimes * (i + 1)

		go func(i int, startId int) {
			subTotal := 0
			for {
				if startId >= endId {
					fmt.Println("已處理完畢:", subTotal)
					break
				}
				fmt.Println("[process]：", i, ",start_id: ", startId, "end_id:", endId, "limit: ", pageSize)

				signLog := new(SignInLog)
				rows, err := DB.Query("select * from sign_in_log  where id > ? and id<? limit ?", startId, endId, pageSize)
				if err != nil {
					fmt.Println(err)
				}
				for rows.Next() {
					rows.Scan()
					err := rows.Scan(
						&signLog.ID,
						&signLog.UserId,
						&signLog.RecentSignTime,
						&signLog.FirstSignTime,
						&signLog.SignType
					)
					if err != nil {
						fmt.Printf("err : %v \n", err)
						continue
					}
					fmt.Printf("%+v \n", signLog)
					//NewInsertData(signLog)
					subTotal++
				}
				defer rows.Close()
				startId += pageSize
			}
		}(i, startId)
	}

}