[xpasky]

Related...

  postgres    1958  0.0  0.0 247616 26040 ?        S    Jul21   3:03 /usr/lib/postgresql/11/bin/postgres
  postgres 1085195  0.0  0.0 249804 24740 ?        Ss   Aug19   2:01 /usr/lib/postgresql/13/bin/postgres
  postgres 1085196  0.0  0.0 223240 27900 ?        Ss   Aug19   1:59 /usr/lib/postgresql/15/bin/postgres

Postgres is the only thing on my Debian that doesn't seamlessly automatically upgrade across dist-upgrades, but instead leaves old versions around for me to deal with manually... which I seem to never get around to.

[heavyset_go]

That's because you install versioned packages like postgresql-15: https://tracker.debian.org/pkg/postgresql-15

That way you can have multiple versions of the same package.

[xpasky]

You mean there is some other way to install postgresql in Debian?

[heavyset_go]

No, what I meant is that the install path for Postgres on Debian involves installing versioned packages. It's the only approved way of installing Postgres from the Debian repos that I'm aware of.