Re: Add TOAST to system tables with ACL?

On Tue, Oct 3, 2017 at 9:19 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru> writes:
> > This topic was already discussed (at least one time) in 2011. See [1]
> for
> > details. I'd like to raise that again.
>
> I'm a bit worried about adding a toast table to pg_class, and more so
> about pg_database, because both of those have to be accessed in situations
> where it's not clear that we could successfully fetch from a toast table,
> because too little of the catalog access infrastructure is alive.
>
> pg_class is probably all right as long as only the ACL field could ever
> get toasted, since it's unlikely that any low-level accesses would be
> paying attention to that field anyway.
>
> For pg_database, you'd have to make sure that the startup-time check of
> database CONNECT privilege still works if the ACL's been pushed out of
> line.
>

Thank you for pointing. I'll check this.

> Also, I've notice performance degradation of GRANT statements themselves.
> > 1000 GRANT statements are executed in 1.5 seconds while 10000 GRANT
> > statements are executed in 42 seconds. In average single GRANT
> statements
> > becomes 2.8 times slower. That's significant degradation, but it doesn't
> > seem to be fatal degradation for me.
>
> Seems all right, since we could just say "we don't really recommend that
> usage pattern".
>

Yes, sure.

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company