Re: Initdb-time block size specification

On Fri, Jun 30, 2023 at 3:29 PM Andres Freund <andres@anarazel.de> wrote:
>> And indeed. Comparing e.g. TPC-H, I see *massive* regressions.  Some queries
> are the same, sobut others regress by up to 70% (although more commonly around
> 10-20%).

Hmm, that is definitely not good.

> That's larger than I thought, which makes me suspect that there's some bug in
> the new code.

Will do a little profiling here to see if I can figure out the
regression. Which build optimization settings are you seeing this
under?

> Interestingly, repeating the benchmark with a larger work_mem setting, the
> regressions are still quite present, but smaller. I suspect the planner
> chooses smarter plans which move bottlenecks more towards hashjoin code etc,
> which won't be affected by this change.

Interesting.

> IOW, you seriously need to evaluate analytics queries before this is worth
> looking at further.

Makes sense, thanks for reviewing.

David