Re: WIP checksums patch

On Sun, Sep 30, 2012 at 07:09:20PM -0700, Jeff Davis wrote:
> On Fri, 2012-09-14 at 17:58 -0700, Jeff Davis wrote:
> > This is just a rebased version of the patch by Simon here:
>
> I just noticed the following note in the docs for this patch:
>
> 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?
>
> Also, it looks out of date, because the default in guc.c is set to true.
> I think we should probably default to true, because it's safer and it
> can always be disabled at runtime, but I don't have a strong opinion
> about that.

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.

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

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