On Wed, Jan 4, 2023 at 11:30 PM Peter Geoghegan <pg@bowt.ie> wrote:
>
> On Wed, Jan 4, 2023 at 7:03 AM Robert Haas <robertmhaas@gmail.com> wrote:
> > But that having been said, I'm kind of astonished that you didn't know
> > about this already. The freezing behavior is in general extremely hard
> > to get right, and I guess I feel if you don't understand how the
> > underlying functions work, including things like performance
> > considerations
>
> I was the one that reported the issue with CLOG lookups in the first place.
>
> > and which functions return fully reliable results, I do
> > not think you should be committing your own patches in this area.
>
> My mistake here had nothing to do with my own goals. I was trying to
> be diligent by hardening an existing check in passing, and it
> backfired.
>
> > There is probably a lot of potential benefit in improving the way this
> > stuff works, but there is also a heck of a lot of danger of creating
> > subtle data corrupting bugs that could easily take years to find.
>
> It's currently possible for VACUUM to set the all-frozen bit while
> unsetting the all-visible bit, due to a race condition [1]. This is
> your long standing bug. So apparently nobody is qualified to commit
> patches in this area.
>
> About a year ago, there was a massive argument over some earlier work
> in the same general area, by me. Being the subject of a pile-on on
> this mailing list is something that I find deeply upsetting and
> demoralizing. I just cannot take much more of it. At the same time,
> I've made quite an investment in the pending patches, and think that
> it's something that I have to see through.
>
> If I am allowed to finish what I've started, then I will stop all new
> work on VACUUM.
>
+1 for you to continue your work in this area. Personally, I don't
feel you need to stop working in VACUUM especially now that you have
built a good knowledge in this area and have a grip over the
improvement areas. AFAICS, the main takeaway is to get a review of
one's own work which I see in your case that Jeff is already doing in
the main project work. So, continuing with that and having some more
reviews should avoid such complaints. It is always possible that you,
me, or anyone can miss something important even after detailed reviews
by others but I think the chances will be much lower.
You are an extremely valuable person for this project and I wish that
you continue working with the same enthusiasm.
--
With Regards,
Amit Kapila.