Very large tech companies completely automate the schema change process (at least for all common operations) so that development teams can make schema changes at scale without direct DBA involvement. The more sophisticated companies handle this regardless of table size, sharding, operational events, etc. It makes a massive difference in execution speed for the entire company.
Renames aren't compatible with that automation flow though, which is what I meant by "out-of-band". They rely on careful orchestration alongside code change deploys, which gets especially nasty when you have thousands of application servers and thousands of database shards. In some DBMS, companies automate them using a careful dance of view-swapping, but that seems brittle performance-wise / operationally.
Sure, but they don’t go out with the code. They go well before.
Right, but my point was that renames in particular typically can't go out well before the corresponding application change [1]. Thus, renames are "out of band" relative to the company's normal schema change process. (This is orthogonal to how schema changes are always "out of band" relative to code deploys; that wasn't what I was referring to.)
[1] In theory a custom ORM could have some kind of dynamic conditional logic for table or column renames, i.e. some way to configure it to retry a query with the "new" name if the query using the "old" name fails. But that has a huge perf impact, and I'm not aware of any common ORMs that do this. So generally if you want to rename a table or column that is already used in prod, there's no way to do it without causing user-facing errors or having system downtime during the period between the SQL rename DDL and the application code change redeploy.