Re: pg_upgrade and rsync

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.

Greetings,

Andres Freund

-- Andres Freund                       http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
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