Re: pg_upgrade and rsync

On 2015-01-27 10:20:48 -0500, Robert Haas wrote:
> On Tue, Jan 27, 2015 at 9:50 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> > Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> >> On Fri, Jan 23, 2015 at 1:48 PM, Andres Freund <andres(at)2ndquadrant(dot)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?

Maybe it's not impossible for existing catalogs, but it's certainly
complicated. But I don't think it's all that desirable anyway - they're
not the same relation after the pg_upgrade anyway (initdb/pg_dump
filled them). That's different for the user defined relations.

Greetings,

Andres Freund

--
Andres Freund http://www.2ndQuadrant.com/
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