Re: pg_upgrade and rsync

On Tue, Jan 27, 2015 at 9:50 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Robert Haas <robertmhaas@gmail.com> writes:
>> On Fri, Jan 23, 2015 at 1:48 PM, Andres Freund <andres@2ndquadrant.com> wrote:
>>> I don't understand why that'd be better than simply fixing (yes, that's
>>> imo the correct term) pg_upgrade to retain relfilenodes across the
>>> upgrade. Afaics there's no conflict risk and it'd make the clusters much
>>> more similar, which would be good; independent of rsyncing standbys.
>
>> +1.
>
> That's certainly impossible for the system catalogs, which means you
> have to be able to deal with relfilenode discrepancies for them, which
> means that maintaining the same relfilenodes for user tables is of
> dubious value.

Why is that impossible for the system catalogs?

-- 
Robert Haas
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