Re: pg_upgrade and rsync

On Fri, Jan 23, 2015 at 1:48 PM, Andres Freund <andres@2ndquadrant.com> wrote:
> On 2015-01-22 20:54:47 -0500, Stephen Frost wrote:
>> * Bruce Momjian (bruce@momjian.us) wrote:
>> > On Fri, Jan 23, 2015 at 01:19:33AM +0100, Andres Freund wrote:
>> > > Or do you - as the text edited in your patch, but not the quote above -
>> > > mean to run pg_upgrade just on the primary and then rsync?
>> >
>> > No, I was going to run it on both, then rsync.
>>
>> I'm pretty sure this is all a lot easier than you believe it to be.  If
>> you want to recreate what pg_upgrade does to a cluster then the simplest
>> thing to do is rsync before removing any of the hard links.  rsync will
>> simply recreate the same hard link tree that pg_upgrade created when it
>> ran, and update files which were actually changed (the catalog tables).
>
> 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.

-- 
Robert Haas
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