Being used to PostgreSQL, this one actually bit me once during a production upgrade. A database migration failed due to a Galera transaction size limit that I u

Being used to PostgreSQL, this one actually bit me once during a production upgrade. A database migration failed due to a Galera transaction size limit that I unfortunately hadn't caught testing the migrations on a single database, and I had to restore from the pre-upgrade backup before resolving the issue and continuing. It wasn't a major issue (the upgrade finished well within the acceptable downtime window), but until then I had assumed that the migrations would be transactional because of course they should be, it's a database! Now I know better than to assume everything you do in a database is transactional. :P