I don’t know how postgresql does it, but I’m interpreting it as yes, their engine has a way to actually replace nonsargable expressions in the query plan itself, with some other operation that performs a seek against the index on the filter. Otherwise you’re right, you’d still need an RBAR evaluation, which is really the crux of the issue. I wish they’d reframe this discussion as RBAR instead of sargability, because it covers so many more sins...