Re: AW: AW: [Extern] Re: autovacuum on pg_catalog tables

"Zwettler Markus (OIZ)" <Markus(dot)Zwettler(at)zuerich(dot)ch> writes:
> I tried this on postgres 9.6:

> postgresql.conf -> allow_system_table_mods=on + pg_ctl restart

> # alter table pg_catalog.pg_shdepend set (autovacuum_vacuum_scale_factor = 0, autovacuum_vacuum_threshold = 1000);
> ERROR: shared tables cannot be toasted after initdb
> Time: 0.618 ms
> # alter table pg_catalog.pg_largeobject set (autovacuum_vacuum_scale_factor = 0, autovacuum_vacuum_threshold = 1000);
> ERROR: AccessExclusiveLock required to add toast table.
> Time: 0.590 ms

Interesting. FWIW, these examples do seem to work in v12 and up.
Since we don't consider this a supported case, I doubt anyone would
be interested in trying to back-port whatever rearrangement allowed
it to work.

regards, tom lane