sqlDB, _ := tx.DB()
	sqlDB.SetMaxOpenConns(1)

	tx = tx.Session(&gorm.Session{PrepareStmt: true})

	wg := sync.WaitGroup{}
	for i := 0; i < 100; i++ {
		wg.Add(1)
		go func() {
			user := User{Name: "jinzhu"}
			tx.Create(&user)

			var result User
			tx.First(&result)
			wg.Done()
		}()
	}
	wg.Wait()

	conn, ok := tx.ConnPool.(*gorm.PreparedStmtDB)
	AssertEqual(t, ok, true)