Will Postgre put such a request?

Question

PostgreSQL

I understand that the question of a spherical horse in a vacuum, but, nevertheless,
Let's take a bulletin board. There are +1000k ads. Each user has an average of 400 ads. There are about 50 fields in the ad.
It is required to make a selection of ads of users with a premium account. And in order not to make joins, you can set premium=1 where user_id=12345 for ads. This value will not change often, of course.
The question is in performance - can such a massive modification in a large table hang the database?

Answer 1

Everything is possible

Answer 2

Not

Answer 3

No, I don't think it will