https://cloud.tencent.com/developer/article/1488871
https://zhuanlan.zhihu.com/p/40208895
https://blog.csdn.net/u014532775/article/details/107018538
https://www.jianshu.com/p/0ef46997c300
https://blog.csdn.net/fuzhongmin05/article/details/91351933
redolog 和 undolog
https://www.cnblogs.com/f-ck-need-u/archive/2018/05/08/9010872.html
