Re: "unexpected duplicate for tablespace" problem in logical replication

At Mon, 15 Jan 2024 16:32:07 -0500, Robert Haas <robertmhaas@gmail.com> wrote in 
> On Fri, Jan 12, 2024 at 3:38 AM Kyotaro Horiguchi
> <horikyota.ntt@gmail.com> wrote:
> > Maybe. It might be better for the cache not to register temprary
> > relations at all.
> 
> This point seems worthy of serious consideration to me. Is there any
> reason why we need RelidByRelfilenumber() to work with temporary
> relations at all? I understand that the current behavior is exposed
> via the SQL-callable function, but maybe that's not really
> intentional. If there's no other use of RelidByRelfilenumber() that
> needs to care about permanent relations intrinsically, I think we
> shouldn't hesitate to just cut them out of the mechanism entirely.

Do you mean that the current behavior of the SQL-callable function is
being treated as a bug and should it be corrected?

Simply doing so will result in the functions pg_relation_filenode()
and pg_filenode_relation() behaving asymmetrically. While there is no
need to purposely change the behavior of the former, it is necessary
to document the behavior of the latter regardless.

The attached patch does the above for the master head. If we apply
this approach to older versions, I can adapt and create similar
patches for them.

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center