Yeah, I was thinking it wouldn't be database downtime as such, but rather downtime for all of the applications that use it. All of them have to be brought down before the column is renamed, and then updated and brought back up.
I take it there are many applications using this database, not just one, so yeah, that could add up to a lot of downtime.
@argv_minus_one @saddestrobots No, just one. 😂
When they added another application, they added a new database, with a series of cron scripts to sync the data between the applications.