On Mon, Jan 20, 2014 at 8:42 PM, David Rowley <dgrowle...@gmail.com> wrote:
> On Mon, Jan 20, 2014 at 2:45 PM, Florian Pflug <f...@phlo.org> wrote: > >> * EXPLAIN VERBOSE ANALYZE now shows the max. number of forward aggregate >> transitions per row and aggregate. It's a bit imprecise, because it >> doesn't >> track the count per aggregate, but it's still a good metric for how well >> the inverse transition functions work. If the number is close to one, >> you >> know that very few rescans are happening. >> >> > I've not looked at this yet and I don't think I'll have time tonight, but > it sounds interesting. I guess it might be quite nice to have a way to see > this especially with the way the numeric stuff works, it might be actually > pretty hard to otherwise know how many inverse transition "failures" there > had been. Do you think it's also worth tracking the inverse transition > failures too? > > I've merged this patch but I attempted to get it into a bit more of a ready state by moving the code out into a helper function the same way as the other explain stuff is done. I've not touched explain before so do let me know if I've made it worse. https://github.com/david-rowley/postgres/commits/invtrans Regards David Rowley
