> 1 bit per page

Close, it’s 2 bits/page :-)

It’s not that it bloats, it’s that the hits are scattered among many pages. My wording wasn’t great on that point.

Some tests demonstrating this are here [0].

[0]: https://www.cybertec-postgresql.com/en/unexpected-downsides-...

Ah nice. Thanks for the extra info. I’m weirdly fascinated by the inner workings of Postgres.

You might like: ‘PostgreSQL 14 Internals’ by Egor Rogov