Who altered the database?

Dear Members!

We have a server.
Because of high usage we can't log DDL-s. There are too many temporary
tables created by users, so it would slow down the server.
A database owner changed.

What can we do to get info about the change (who did it, from what IP, when
it happened) in the future?

As I see we can't define precisely what we want to log... All or nothing.

Do you know any tricks to do it?

For example: DB level trigger, or other thing?

Thank you for the answer!

Best regards

dd