| From: | Bruce Momjian <bruce(at)momjian(dot)us> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Greg Stark <stark(at)mit(dot)edu>, Florian Pflug <fgp(at)phlo(dot)org>, Ants Aasma <ants(at)cybertec(dot)at>, Andres Freund <andres(at)2ndquadrant(dot)com>, Jeff Davis <pgsql(at)j-davis(dot)com>, Heikki Linnakangas <hlinnakangas(at)vmware(dot)com>, Simon Riggs <simon(at)2ndquadrant(dot)com>, Greg Smith <greg(at)2ndquadrant(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Enabling Checksums |
| Date: | 2013-04-17 18:10:17 |
| Message-ID: | 20130417181017.GQ5343@momjian.us |
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| Lists: | pgsql-hackers |
On Wed, Apr 17, 2013 at 01:29:18PM -0400, Tom Lane wrote:
> Bruce Momjian <bruce(at)momjian(dot)us> writes:
> > Uh, not sure how pg_upgrade would detect that as the version number is
> > not stored in pg_controldata, e.g.:
>
> > Data page checksums: enabled/disabled
>
> That seems pretty shortsighted. The field probably ought to be defined
> as containing a checksum algorithm ID number, not a boolean.
>
> But having said that, I'm not sure why this would be pg_upgrade's
> problem. By definition, we do not want pg_upgrade running around
> looking at individual data pages. Therefore, whatever we might do
> about checksum algorithm changes would have to be something that can be
> managed on-the-fly by the newer server.
Well, my idea was that pg_upgrade would allow upgrades from old clusters
with the same checksum algorithm version, but not non-matching ones.
This would allow the checksum algorithm to be changed and force
pg_upgrade to fail.
--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ It's impossible for everything to be true. +
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