Re: Freeze avoidance of very large table.

On Mon, Nov 30, 2015 at 07:05:21PM +0100, Andres Freund wrote:
> On 2015-11-30 12:58:43 -0500, Bruce Momjian wrote:
> > I would not bother mentioning this detail in the pg_upgrade manual page:
> > 
> > +   Since the format of visibility map has been changed in version 9.6,
> > +   <application>pg_upgrade</> creates and rewrite new <literal>'_vm'</literal>
> > +   file even if upgrading from 9.5 or before to 9.6 or later with link mode (-k).
> 
> Might be worthwhile to keep as that influences the runtime for link mode
> when migrating <9.6 -> 9.6.

It is hard to see that it would have a measurable duration.  The
pg_upgrade docs are already very long and this detail doesn't seems
significant.  Can someone test the overhead?

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com

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