Golang Go语言中 go-sql-driver/mysql 为什么不死锁？

事务 1：

begin;

select * from table1 where id = 1 for update;

sleep(1)

select * from table2 where id = 1 for update;

commit;

事务 2：

begin;

select * from table2 where id = 1 for update;

sleep(1)

select * from table1 where id = 1 for update;

commit;

两个表在同一个 database 里面，且两个表中记录都存在。在 MySQL 客户端肯定报死锁错误。 但是用 go-sql-driver/mysql 实现直连 MySQL，用两个 goroutine 来跑这两个事务，几乎不报死锁（加长 sleep 时间偶尔能出现 Deadlock 错误），而且 sleep 后查出来的结果行数会为 0。

在 go-sql-driver/mysql 里加日志，发现 MySQL Server 响应包里确实不是 error。实在不知为何。请指教。

代码如下：

func Atomic(ctx context.Context, db *sql.DB, txFunc func(tx *sql.Tx)error) (err error) {
	var tx *sql.Tx
	if tx, err = db.Begin(); err != nil {
		clog.Errorf(ctx, "begin error: %v", err)
		return
	}
	defer func() {
		if err == nil {
			if err = tx.Commit(); err != nil {
				clog.Errorf(ctx, "commit error: %v", err)
				return
			}
		} else {
			_ = tx.Rollback()
		}
	}()
err = txFunc(tx)
return
}
func testDBLocal(ctx context.Context) {
dsn := “abc:abc@tcp(127.0.0.1:3306)/account_db?timeout=10s&readTimeout=10s&allowNativePasswords=True”
wDB , _ := sql.Open(“mysql”, dsn)
wDB2, _ := sql.Open(“mysql”, dsn)
if wDB == nil || wDB2 == nil {
	panic(errors.New("config error"))
}

wDB.SetMaxOpenConns(100)
wDB.SetMaxIdleConns(100)
wDB.SetConnMaxLifetime(time.Hour)

wDB2.SetMaxOpenConns(100)
wDB2.SetMaxIdleConns(100)
wDB2.SetConnMaxLifetime(time.Hour)

var wg sync.WaitGroup
wg.Add(2)
clog.Infof(ctx, "start")

go func() {
	defer wg.Done()

	ctx := clog.GetCtxWithLogid(context.Background(), "first")
	_ = Atomic(ctx, wDB, func(tx *sql.Tx) error {
		// A
		if rows, err := tx.Query("select * from account_tab where userid = 203802 for update"); err != nil {
			clog.Errorf(ctx, "query account_tab error: %v", err)
			return err
		} else {
			if e := rows.Close(); e != nil {
				clog.Errorf(ctx, "close rows error: %v", e)
			}
			if e := rows.Close(); e != nil {
				clog.Errorf(ctx, "close rows error: %v", e)
			}
			clog.Infof(ctx, "A done")
		}

		time.Sleep(5*time.Second)

		// B
		if rows, err := tx.Query("select * from account_audit_tab where userid = 203802 for update"); err != nil {
			clog.Errorf(ctx, "query account_audit_tab error: %v", err)
			return err
		} else {
			cnt := 0
			for rows.Next() {
				cnt += 1
			}
			if e := rows.Close(); e != nil {
				clog.Errorf(ctx, "close rows error: %v", e)
			}
			if e := rows.Close(); e != nil {
				clog.Errorf(ctx, "close rows error: %v", e)
			}
			clog.Infof(ctx, "B done, query account_audit_tab count: %v", cnt)
		}

		return nil
	})

	clog.Infof(ctx, "first done")
}()

go func() {
	defer wg.Done()

	ctx := clog.GetCtxWithLogid(context.Background(), "second")

	_ = Atomic(ctx, wDB2, func(tx *sql.Tx) error {
		// B
		if rows, err := tx.Query("select * from account_audit_tab where userid = 203802 for update"); err != nil {
			clog.Errorf(ctx, "query account_audit_tab error: %v", err)
			return err
		} else {
			cnt := 0
			for rows.Next() {
				cnt += 1
			}
			if e := rows.Close(); e != nil {
				clog.Errorf(ctx, "close rows error: %v", e)
			}
			if e := rows.Close(); e != nil {
				clog.Errorf(ctx, "close rows error: %v", e)
			}
			clog.Infof(ctx, "B done, query account_audit_tab count: %v", cnt)
		}

		time.Sleep(5*time.Second)

		// A
		if rows, err := tx.Query("select * from account_tab where userid = 203802 for update"); err != nil {
			clog.Errorf(ctx, "query account_tab error: %v", err)
			return err
		} else {
			if e := rows.Close(); e != nil {
				clog.Errorf(ctx, "close rows error: %v", e)
			}
			if e := rows.Close(); e != nil {
				clog.Errorf(ctx, "close rows error: %v", e)
			}
			clog.Infof(ctx, "A done")
		}

		return nil
	})

	clog.Infof(ctx, "second done")
}()

wg.Wait()
clog.Infof(ctx, "all done")
}