Re: Move pg_largeobject to a different tablespace *without* turning on system_table_mods.

På onsdag 19. oktober 2016 kl. 18:29:31, skrev Bruce Momjian <bruce(at)momjian(dot)us
<mailto:bruce(at)momjian(dot)us>>:
On Tue, Oct 18, 2016 at 04:51:54PM +0200, Andreas Joseph Krogh wrote:
>     > 2. Being able to move pg_largeobject to a different tablespace
>     >    *without* turning on system_table_mods. This is important for
>     >    people storing LOTS of large-objects on separate
>     >    disks (non-SSD) and hence in a different tablespace.
>     > Anyone willing to discuss this?
>     > 
>     This was proposed a few years ago but no one cared to draft a patch.
>
>  
> So that why I'm re-raising the issue:-)
> Having "everything in the database" adds lots of benefits, conceptually
> (follows tx-semantics, consistent backups etc.), however it's currently not
so
> easy in practice.

Yeah, rereading that old thread was interesting, and unfortunate that no
one mentioned the system catalog change would break pg_upgrade, though
pg_upgrade was not popular at the time that thread was started.

I think an open question is why you would not want to move the other
system tables at the same time you move pg_largeobject.
 
The thing is that I don't understand what the problem really is. I have no
problem moving the other system-tables as well if that fixes the problem.
I tried moving pg_largeobject back to the same tablespace as the database but
that too gave the error.
 
Are you saying that if I move all system-tables to the tablespace I moved
pg_largeobject to it'll work? If so, is there a convenient way to move all
system-tables to a tablespace?
 
Thanks.
 
-- Andreas Joseph Krogh
CTO / Partner - Visena AS
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