Re: Enabling Checksums

On Wed, Apr 17, 2013 at 01:22:01PM -0400, Tom Lane wrote:
> Greg Stark <stark(at)mit(dot)edu> writes:
> > On Wed, Apr 17, 2013 at 4:28 PM, Florian Pflug <fgp(at)phlo(dot)org> wrote:
> >> Is there any way we can change the checksum algorithm in 9.4
> >> *without* breaking pg_upgrade?
>
> > Personally I think we're going to need a solution for page format
> > changes someday eventually....
>
> > What advantages are we postponing now to avoid it?
>
> Um, other than the ability to make a release?
>
> We aren't going to hold up 9.3 until that particular bit of pie in the
> sky lands. Indeed I don't expect to see it available in the next couple
> years either. When we were looking at that seriously, two or three
> years ago, arbitrary page format changes looked *hard*.
>
> The idea of bumping the page format version number to signal a checksum
> algorithm change might work though.

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

Do we need to address this for 9.3? (Yuck)

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ It's impossible for everything to be true. +