Re: BUG #18165: Could not duplicate handle for "Global/PostgreSQL.xxxxxxxxxx": Bad file descriptor

On Sat, Oct 21, 2023 at 5:10 PM Thomas Munro <thomas.munro@gmail.com> wrote:
> Ahh, I think I might see it.  "Global/PostgreSQL.2437152779" is an odd
> DSM handle (as in, the low order bit is set).  That means that it's a
> "main region" DSM segment, of the type that you get if you set
> min_dynamic_shared_memory (commit 84b1c63a).  That looks potentially
> broken on Windows, because we have this extra NT handle sharing stuff
> in dsm_impl_pin_segment(), which can't possibly work and should
> probably be gated on !is_main_region_dsm_handle(seg->handle).  On
> every other OS that function does nothing, which would explain how we
> didn't notice for so long.
>
> Maxime, do you have min_dynamic_shared_memory set?

And concretely this would be the fix, I think.  But I don't have
Windows, and for reasons I haven't fathomed I haven't yet managed to
reproduce it by pushing a change of default min_dynamic_shared_memory
to CI.  Is there any chance that a Postgres hacker on Windows could
confirm the above theory, and that the attached fixes it?