Re: Freeze avoidance of very large table.

On Sun, Nov 22, 2015 at 8:16 AM, Masahiko Sawada <sawada.mshk@gmail.com> wrote:

> Thank you for taking the time to review this patch!
> The updated version patch is attached.

I am skeptical about just copying the old page header to be two new
page headers.  I don't know what the implications for this will be on
pd_lsn.  Since pg_upgrade can only run on a cluster that was cleanly
shutdown, I think that just copying it from the old page to both new
pages it turns into might be fine.  But pd_checksum will certainly be
wrong, breaking pg_upgrade for cases where checksums are turned on in.
It needs to be recomputed on both new pages.  It looks like there is
no precedence for doing that in pg_upgrade so this will be breaking
new ground.

Cheers,

Jeff