> On 02 Mar 2018, at 01:03, Bruce Momjian <bruce@momjian.us> wrote:
>
> On Tue, Feb 6, 2018 at 01:51:09PM +0100, Daniel Gustafsson wrote:
>>> On 06 Feb 2018, at 01:09, David Fetter <david@fetter.org> wrote:
>>
>>> - pg_upgrade is very much a blocker for on-disk format changes.
>>
>> I wouldn’t call it a blocker, but pg_upgrade across an on-disk format change
>> would be a very different experience from what we have today since it would
>> need to read and rewrite data rather than hardlink/copy. Definitely not a
>> trivial change though, that I completely agree with.
>
> Uh, not necessarily. To allow for on-disk format changes, pg_upgrade
> _could_ rewrite the data files as it copies them (not link), or we could
> modify the backend to be able to read the old format. We have already
> done that for some changes to data and index types.
Right, that is another option. I guess we’ll have to wait and see what the
impact will be for the available options when we get there, until there is an
actual on-disk change to reason around it’s a fairly academic discussion.
cheers ./daniel
