Re: WIP checksums patch

On Mon, Oct 1, 2012 at 09:25:43AM -0700, Jeff Davis wrote:
> On Mon, 2012-10-01 at 10:43 -0400, Bruce Momjian wrote:
> > > The default is <literal>off</> for backwards compatibility and
> > > to allow upgrade. The recommended setting is <literal>on</> though
> > > this should not be enabled until upgrade is successfully complete
> > > with full set of new backups.
> > >
> > > I don't understand what that means -- if they have the page_checksums
> > > GUC available, then surely upgrade is complete, right? And what is the
> > > backwards-compatibility issue?
>
> > I think this need to clearly state "pg_upgrade", not a dump/restore
> > upgrade, which would be fine. It would be interesting to have
> > pg_upgrade change this setting, or tell the user to change it. I am not
> > sure enough people are using pg_upgrade to change a default value.
>
> I still don't understand why pg_upgrade and page_checksums don't mix.

The heap/index files are copied unmodified from the old cluster, so
there are no checksums on the pages.

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

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