摘要：
sql: mysql postgres relation is good for write not for read schdema is more predictable and tidy 阅读全文
摘要：
1 AZ AWS 55; microsoft 48 google 18 (2019) 2 Market share aws 40%, microsftt 30%, google 20% 3 offered service compute : eC2 , vm, colud engine speed 阅读全文