On 6 March 2014 19:42, Robert Haas <robertmh...@gmail.com> wrote: > On Wed, Mar 5, 2014 at 7:42 PM, Fabrízio de Royes Mello > <fabriziome...@gmail.com> wrote: > > On Tue, Mar 4, 2014 at 5:00 PM, Fabrízio de Royes Mello > > <fabriziome...@gmail.com> wrote: > >> On Tue, Mar 4, 2014 at 3:29 PM, Andres Freund <and...@2ndquadrant.com> > >> wrote: > >> > > >> > On 2014-03-04 12:54:02 -0500, Robert Haas wrote: > >> > > On Tue, Mar 4, 2014 at 9:50 AM, Andres Freund < > and...@2ndquadrant.com> > >> > > wrote: > >> > > > On 2014-03-04 09:47:08 -0500, Robert Haas wrote: > >> > > > Can't that be solved by just creating the permanent relation in a > >> > > > new > >> > > > relfilenode? That's equivalent to a rewrite, yes, but we need to > do > >> > > > that > >> > > > for anything but wal_level=minimal anyway. > >> > > > >> > > Yes, that would work. I've tended to view optimizing away the > >> > > relfilenode copy as an indispensable part of this work, but that > might > >> > > be wrongheaded. It would certainly be a lot easier to make this > >> > > happen if we didn't insist on that. > >> > > >> > I think it'd already much better than today's situation, and it's a > >> > required codepath for wal_level > logical anyway. So even if somebody > >> > wants to make this work without the full copy for minimal, it'd still > be > >> > a required codepath. So I am perfectly ok with a patch just adding > that. > >> > > >> > >> Then is this a good idea for a GSoC project ? > >> > >> I don't know very well this internals, but I am willing to learn and I > >> think the GSoC is a good opportunity. > >> > >> Any of you are willing to mentoring this project? > >> > > > > I written the proposal to this feature, so I would like to know if > someone > > can review. > > I think this isn't a good design. Per the discussion between Andres > and I, I think that I think you should do is make ALTER TABLE .. SET > LOGGED work just like VACUUM FULL, with the exception that it will set > a different relpersistence for the new relfilenode. If you do it that > way, this will be less efficient, but much simpler, and you might > actually finish it in one summer.
Sounds like a plan. Would there be any stretch-goals for this work, or is there not really anything else that could be done? -- Thom
