}(user.ID)

	wg.Add(1)
	go func() {
		defer wg.Done()
		for range closeValid {
			for i := 0; i < loopCount; i++ {
				pdb.Close() // the Close method must can be call multiple times
				atomic.CompareAndSwapInt64(&closeFinishedAt, 0, time.Now().UnixNano())
			}
		}
	}()

	wg.Wait()
	var tmp User
	err = tx.Session(&gorm.Session{}).First(&tmp, user.ID).Error
	if err != gorm.ErrInvalidDB {