Did you need to compile a kernel to enable it? I’ve just done the project of installing Debian on a 20 year old iMac with 2.5 GB of RAM, and while zram definitely seems to help, I’d love to try this as well.

I think what he means is that the unique identifier for a database record is a composite of two fields: SSN + birth date. That doesn’t mean that SSN to birth date is a one-to-many relation.