Re: Discussion on missing optimizations

On 12 October 2017 at 04:50, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> We haven't really done a very good job figuring out what to do about
> optimizations that some people (mostly you) think are marginal. It's
> obviously true that we can't just burn infinite planner cycles on
> things that don't usually help, but at the same time, we can't just
> keep ignoring requests by users for the same features and saying
> "you'll be sad if we give this to you". Those people don't give up on
> wanting the optimization; they just don't use PostgreSQL. I think we
> need to stop just saying "no" and start thinking about what we could
> do that would let us say "yes".

I'm with Robert on this. Planning time *is* important, but if we were
to do a quick tally on the number of patches that we've seen in the
last few years to improve execution time by either improving the
executor code or adding some smarts to the planner to reduce executor
work vs patches aimed to reduce planning time, I think we'd find the
general focus is on the executor. Personally, I don't recall a single
patch aimed to just speed up the planner. Perhaps I missed some? It
looks like there's plenty we could do in there, just nobody seems
interested enough to go and do it, everyone who cares about
performance is too busy trying to make execution run faster.

--
David Rowley http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services