Re: Interesting fail when migrating Pg from Ubuntu Bionic to Focal

On Fri, Mar 04, 2022 at 05:03:14PM -0500, Tom Lane wrote:
> hubert depesz lubaczewski <depesz(at)depesz(dot)com> writes:
> > On Fri, Mar 04, 2022 at 02:09:52PM -0500, Tom Lane wrote:
> >> I tried and failed to reproduce this on Fedora 35 on aarch64,
> >> but that has what I think is a newer LLVM version:
>
> > I have suspicion that it also kinda depends on number of rows in there.
> > When I deleted some schemas, which included some functions, the problem
> > disappeared.
> > I wasn't able to pinpoint specific thing, though, and when I called the
> > pg_proc + pg_roles query for each separate row - it worked flawlessly.
>
> Mmm ... it might have just been that the planner chose not to use
> JIT when it thought there were fewer rows involved. Did you check
> with EXPLAIN that these cut-down cases still used JIT?

Hi,
I tore these boxes down, so can't check immediately, but I think
I remember that you're right - single-row queries didn't use JIT.

Best regards,

depesz