That's how Postgres' (and perhaps others) MVCC works, yes. MySQL / InnoDB, however, updates tuples in-place [0], and uses the undo log to recreate older version

That's how Postgres' (and perhaps others) MVCC works, yes. MySQL / InnoDB, however, updates tuples in-place [0], and uses the undo log to recreate older versions as needed. 0: https://dev.mysql.com/doc/refman/8.4/en/innodb-multi-versioning.html https://dev.mysql.com/doc/refman/8.4/en/innodb-multi-version...