Re: 16-bit page checksums for 9.2

Excerpts from Tom Lane's message of mié feb 29 18:34:27 -0300 2012:
>
> Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> > On Wed, Feb 29, 2012 at 2:33 PM, Heikki Linnakangas
> > <heikki(dot)linnakangas(at)enterprisedb(dot)com> wrote:
> >> The utility would run in the old cluster before upgrading, so the the flag
> >> would have to be present in the old version. pg_upgrade would check that the
> >> flag is set, refusing to upgrade if it isn't, with an error like "please run
> >> pre-upgrade utility first".
>
> > I find that a pretty unappealing design; it seems to me it'd be much
> > easier to make the new cluster cope with everything.
>
> Easier for who? I don't care for the idea of code that has to cope with
> two page formats, or before long N page formats, because if we don't
> have some mechanism like this then we will never be able to decide that
> an old data format is safely dead.

.. in fact this is precisely what killed Zdenek Kotala's idea of
upgrading.

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Álvaro Herrera <alvherre(at)commandprompt(dot)com>
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