I don't have all the details anymore. But one of the non obvious things for me was that foreign key cascades where not in the binlogs. I also think that some changes in the database layout could lead to strange things on the replicas.

> foreign key cascades where not in the binlogs.

True, but that's finally solved now.

> I also think that some changes in the database layout could lead to strange things on the replicas.

I've been using MySQL for 23 years and have no idea what you're referring to here, sorry. But it's not like other DBs have quirk-free replication either. Postgres logical replication doesn't handle DDL at all, for example.

I appreciate you carrying the torch for MySQL here, since most opinions are based on setups over a decade old, with little to no bearing on how it runs today