Abstract: Traditional RDBMS is essentially a singlemachine system and usually employs highend server and highreliable storage device due to performance and reliability issues which make it incompetent to serve todays Internet applications with high scalability, high performance, high available and low cost. OceanBase is an opensource, sharednothing, distributed relational database system, which is developed from scratch at Alibaba. Built on top of computer clusters consisting of inexpensive commodity PC servers, OceanBase meets the requirement of modern internet applications quite well. OceanBase has been widely used in the production systems of Taobao, Tmall and Alipay for years.