Re: Surprised by index choice for count(*)

Thank you both. Simple, as expected. And I’m easily surprised.
Version 10 (perhaps obviously) for those scoring at home.

> On May 1, 2018, at 10:11 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
> Rob Sargent <robjsargent(at)gmail(dot)com> writes:
>> Should I be? I would have thought the pk would have been chosen v.
>> function index?
>
> If I'm reading this correctly, the PK index contains uuids while
> the fpv index contains float4s, meaning the latter is probably half
> the size. So scanning it is a lot cheaper, at least according to
> the planner's cost model.
>
> regards, tom lane