tl;dr - Code for converting a primary index (for example a pre-created one) to a covering index so you can do Index-Only scans and get your two (or more) columns back faster than ever Context Recently while abusing Postgres to do things it’s not supposed to do (I may go into this particular hack at a later date), I ended up trying to convert an existing primary key index to a covering index to make sure a certain column was always easily accessible since most queries only returned this value.
