You won't believe what a nightmare it was to work with transactionless DDLs in MySQL. Transactional DDL will be a dream come true for Vitess: we can throw away all the hacks we had to do for MySQL's sake.
I also see such a clean 2PC API. This was another huge mess on the MySQL side.
- Postgres has transactional DDL vs auto-commit. Can that property be retained?
- Postgres leans into extensions much more that Mysql. Will types/indexes/etc introduced by e.g. pg_vector or postgis, have a path for support?
anything similar that will be a challenge?