Re: WIP checksums patch

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Also, it looks out of date, because the default in guc.c is set to true.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.

Regards,
	Jeff Davis