Simon Riggs <simon@2ndquadrant.com> writes:
> Proposal: Make the first block of a seq scan cost random_page_cost, then
> after that every additional block costs seq_page_cost.
This is only going to matter for a table of 1 block (or at least very
few blocks), and for such a table it's highly likely that it's in RAM
anyway. So I'm unconvinced that the proposed change represents a
better model of reality.
Perhaps more to the point, you haven't provided any actual evidence
that this is a better approach. I'm disinclined to tinker with the
fundamental cost models on the basis of handwaving.
regards, tom lane