How do "Suggested Usernames" actually work?

We’ve talked about Redis Hashes for storage and Bloom Filters for the "Bouncer" at the door. But what happens when ateebHussain is taken and you need to suggest: ateebHussain_1 ateebHussain_pro ateeb_h If you try to do this with LIKE %ateeb% in a SQL database with 10 million rows... RIP your latenc