Showdown: MySQL 8 vs PostgreSQL 10
Kenn Ejima

I am sorry, but I think you got wrong why Uber ditched PostgreSQL. It wasn't just for lack of configuration flexibility, but because of the poor performance of writes, since a write in one column data will trigger ALL the indexes of that row to be updated, cascading a LOT of writes for the most simple data updates. It's all on the link you provided.