flink和spark的异同：
https://www.zhihu.com/question/30151872
presto 还是hive？
http://geek.csdn.net/news/detail/98839
devops的思考：
http://www.jianshu.com/p/a01f912f1f66
postgres的黑科技：
https://yq.aliyun.com/articles/2727
kafka的应用场景：
http://blog.csdn.net/code52/article/details/50475511
OLAP常用框架：spark-sql，presto，druid，kylin的区别
https://www.zhihu.com/question/41541395?sort=created
