> On 02 Mar 2018, at 01:03, Bruce Momjian <br...@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 <da...@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
