Re: pg15 inherited stats expressions: cache lookup failed for statistics object

On Mon, Oct 31, 2022 at 1:33 PM Michael Paquier <michael(at)paquier(dot)xyz> wrote:

> On Mon, Oct 31, 2022 at 01:12:09PM +0800, Richard Guo wrote:
> > BTW, I noticed a micro-optimization opportunity in examine_variable that
> > we can fetch the RangeTblEntry for 'onerel' outside the foreach loop
> > when iterating the extended stats so that we can do it only once rather
> > than for each stat.
>
> Isn't that the kind of thing where we'd better have some regression
> coverage?

Yeah, we need to have some regression tests for that. I come up with a
case in stats_ext like below

CREATE STATISTICS stxdinp ON (a + 1), a, b FROM stxdinp;
SELECT * FROM check_estimated_rows('SELECT a + 1, b FROM ONLY stxdinp GROUP
BY 1, 2');

This case should be able to cover both expression stats and ndistinct
stats. Hence, attach v2 patch.

Thanks
Richard