왜 우버는 PostgreSQL 에서 MySQL 로 갈아탔나?

https://eng.uber.com/mysql-migration/   나중에 읽어보자.!! 

반박 및 논쟁글은 여기 => https://news.ycombinator.com/item?id=12166585

Conclusion

Postgres served us well in the early days of Uber, but we ran into significant problems scaling Postgres with our growth. Today, we have some legacy Postgres instances, but the bulk of our databases are either built on top of MySQL (typically using our Schemaless layer) or, in some specialized cases, NoSQL databases like Cassandra. We are generally quite happy with MySQL, and we may have more blog articles in the future explaining some of its more advanced uses at Uber.