Re: Slow GRANT ROLE on PostgreSQL 16 with thousands of ROLEs

Em qua., 27 de mar. de 2024 às 13:41, Nathan Bossart <
nathandbossart(at)gmail(dot)com> escreveu:

> On Wed, Mar 27, 2024 at 01:21:23PM -0300, Ranier Vilela wrote:
> > Nathan Bossart <nathandbossart(at)gmail(dot)com> writes:
> >>Committed with that change. Thanks for the guidance on this one.
> >
> > I think that left an oversight in a commit d365ae7
> > <
> https://github.com/postgres/postgres/commit/d365ae705409f5d9c81da4b668f59c3598feb512
> >
> > If the admin_role is a NULL pointer, so, can be dereferenced
> > in the main loop of the function roles_is_member_of and
> > worst, IMO, can be destroying aleatory memory?
> >
> > First, is a better shortcut test to check if admin_role is NOT NULL.
> > Second, !OidIsValid(*admin_role), It doesn't seem necessary anymore.
> >
> > Or am I losing something?
>
> If admin_role is NULL, then admin_of is expected to be set to InvalidOid.
> See the assertion at the top of the function. AFAICT the code that
> dereferences admin_role short-circuits if admin_of is invalid.
>
These conditions seem a little fragile and confusing to me.
When a simple test, it protects the pointer and avoids a series of tests,
which are unnecessary if the pointer is invalid.

best regards,
Ranier Vilela