> Distributed databases reduce a lot of the operational complexity
That’s a new one to me; never have I ever heard someone claim that making a system distributed reduces complexity.
I’ve operated EDB’s Distributed Postgres at a decent scale (< 100 TB of unique data); in no way did it enable reduced complexity. For the devs, maybe – “chuck whatever data you want wherever you want, it’ll show up.” But for Ops? Absolutely not, it was a nightmare.
I think people’s idea of scale and operating at scale is limited to their experience.
You can get MySQL to run at any scale, look at Meta and Shopify. Operational complexity at that scale is a different story.
Distributed databases reduce a lot of the operational complexity. To take one example:
Try a DDL on a 5 TB table in any replicated MySQL topology of choice and compare it with TiDB’s Distributed execution framework.