Upgrading Uber's MySQL Fleet

So satisfying to do a huge upgrade like this and then see the actual proof in the pudding with all the reduced latencies and query times.

Yeah some numbers caught my attention like ~94% reduction in overall database lock time.

And to think they never have to worry about VACUUM. Ahh the peace.

As somebody who has always used MySQL, but always been told that I should be using Postgres, I'd love to understand what the issues with VACUUM are, and what I should be aware of when potentially switching databases?

VACUUM and VACUUM FULL (and/or with ANALYZE) can lock tables for a very long time, especially when the table is large. Incantation may also require 2x the space for the table being operated on. In short: it's slow.

pg_repack gets rid of the need to lock tables for the duration of the vacuum: https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Appen...

It is an extension though so downside there is it not being included in most Postgres installs. I’ve used it at work and it felt like a superpower getting the benefits of a vacuum full without all the usual drama.