[minhazm]

Slack started out on LAMP stack, so a lot of their choice of technologies stem from there. There's a mention of using Hack in this article, which is a PHP dialect. People frequently reach for things more complicated than MySQL, but the truth is that there are likely very few use cases that won't work with MySQL. Vitess makes MySQL manageable at scale (YouTube uses it too) as long as you invest in getting the tooling & automation ready. Vitess itself is fairly straight forward to understand and operate. It's ultimately just MySQL + a side car service and a query layer that handles reading/writing to shards for you, and some other admin tools for managing shards, migrations, etc. If you need to debug something you can just SSH into a host and connect directly to the mysql instance. It uses standard mysql replication and you can tune it the same way you would tune mysql normally. There's no shortage of resources available when it comes to dealing with mysql.

[rrdharan]

> YouTube uses it too

Pretty sure YouTube migrated onto Spanner quite a while ago.

[semiquaver]

Vitess increases the number of things that can go wrong in a high traffic MySQL cluster by an order of magnitude. When you need it you need it but “straightforward to operate” only describes vitess in the most abstract of theoretical happy path situations.

[derekperkins]

That's true for any database at that scale