Re: Enabling Checksums

On 3/25/13 8:25 AM, Bruce Momjian wrote:
> On Fri, Mar 22, 2013 at 11:35:35PM -0500, Jim Nasby wrote:
>> >On 3/20/13 8:41 AM, Bruce Momjian wrote:
>>> > >Also, if a users uses checksums in 9.3, could they initdb without
>>> > >checksums in 9.4 and use pg_upgrade? As coded, the pg_controldata
>>> > >checksum settings would not match and pg_upgrade would throw an
>>> > >error, but it might be possible to allow this, i.e. you could go from
>>> > >checksum to no checksum initdb clusters, but not from no checksum to
>>> > >checksum. I am wondering if the patch should reflect this.
>> >
>> >If the docs don't warn about this, they should, but I don't think it's
>> >the responsibility of this patch to deal with that problem. The reason
>> >I don't believe this patch should deal with it is because that is a
>> >known, rather serious, limitation of pg_upgrade. It's something about
>> >pg_upgrade that just needs to be fixed, regardless of what patches
>> >might make the situation worse.
> Huh? It wasn't a "serious limitation" of pg_upgrade until this patch.
> What limitation does pg_upgrade have regardless of this patch?

The limitation that it depends on binary compatibility.

I suppose it's unfair to say that's a pg_upgrade limitation, but it's a certainly a limitation of Postgres upgrade capability. So far we've been able to skirt the issue but at some point we need to address this.