Q1.如何对流数据采样? How to sample streaming data? Q2.如何提供类型信息（表模式） ? How to provide the type information （schema）? Q3.如何展示数据中错误? How to show errors in data? Q4.如何实时获取中间结果? How to fetch the intermediate results in real time? Q5.如何避免重复计算? How to avoid duplicated computation? Q6.如何反复提交作业? How to submit jobs iteratively?
