[simonw]

It's definitely an interesting category right now - I've been following Citus and Vitess with interest for a while since they let you use PostgreSQL and MySQL respectfully with magic sharding sauce.

I haven't actually tried either yet - like you I'm waiting for more success stories (plus I don't currently have any problems that warrant that approach).

Slack adopted Vitess a few years ago.

[nitsuaeekcm]

Vitess and Citus seem to be half-way between manual sharding and distributed SQL. They really discourage cross-shard updates, for instance, whereas they're a really natural part of distributed SQL: > The authors of Vitess recommend that you design your VSchema so that cross-shard updates (and 2PC) are not required. https://vitess.io/docs/reference/features/two-phase-commit/

Maybe though it's just a fundamental coordination problem one can't work around.

[simonw]

I'm very OK with that limitation - when I'm designing a sharded system I'm happy to take shards into account and arrange my entities such that I can apply updates to them grouped on a single shard.

The value I want is help directing those write queries to the correct shards, and some assistant with cross-shard read queries.