Re: New strategies for freezing, advancing relfrozenxid early

On Wed, Jan 25, 2023 at 7:41 PM Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> Both Andres and I have repeatedly expressed concern about how much is
> being changed in the behavior of vacuum, and how quickly, and IMHO on
> the basis of very limited evidence that the changes are improvements.
> The fact that Andres was very quickly able to find cases where the
> patch produces large regression is just more evidence of that. It's
> also hard to even understand what has been changed, because the
> descriptions are so theoretical.

Did you actually read the motivating examples Wiki page?

> I think we're on a very dangerous path here. I want VACUUM to be
> better as the next person, but I really don't believe that's the
> direction we're headed. I think if we release like this, we're going
> to experience more VACUUM pain, not less. And worse still, I don't
> think anyone other than Peter and Andres is going to understand why
> it's happening.

I think that the only sensible course of action at this point is for
me to revert the page-level freezing commit from today, and abandon
all outstanding work on VACUUM. I will still stand by the basic
page-level freezing work, at least to the extent that I am able to.
Honestly, just typing that makes me feel a big sense of relief.

I am a proud, stubborn man. While the experience of working on the
earlier related stuff for Postgres 15 was itself enough to make me
seriously reassess my choice to work on VACUUM in general, I still
wanted to finish off what I'd started. I don't see how that'll be
possible now -- I'm just not in a position to be in the center of
another controversy, and I just don't seem to be able to avoid them
here, as a practical matter. I will resolve to be a less stubborn
person. I don't have the constitution for it anymore.

--
Peter Geoghegan