Re: Nonrandom scanned_pages distorts pg_class.reltuples set by VACUUM

On Thu, Feb 17, 2022 at 4:10 PM Peter Geoghegan <pg(at)bowt(dot)ie> wrote:
> > I would say it differently: I think the commit message does a poor job
> > describing what the commit actually does. For example, it says nothing
> > about changing VACUUM to always scan the last page of every heap
> > relation. This whole thread is about fixing a problem that was caused
> > by a significant behavior change that was *not even mentioned* in the
> > original commit message.
>
> It's not that simple. As I said in the fix-up commit message, and in
> the opening email to this thread, it basically isn't a new behavior at
> all. It would be much more accurate to describe it as a behavior that
> originated with commit e8429082, from late 2015. There was a subtle
> interaction with that existing behavior, and the refactoring work,
> that caused the reltuples problem.

Honestly, I really think it's that simple. It really is possible to
describe what changes a commit is making in the commit message -- and,
in my opinion, you're not doing it.

> > I think you *really* need to put more effort into
> > making your patches, and the emails about your patches, and the commit
> > messages for your patches understandable to other people. Otherwise,
> > waiting 3 months between when you post the patch and when you commit
> > it means nothing. You can wait 10 years to commit and still get
> > objections, if other people don't understand what you're doing.
>
> I don't think it's fair to just suppose that much of what I write is
> incomprehensible, just like that.

I'm not supposing anything. I'm telling you what I can understand, and
what I can't. Unless you intend to accuse me of pretending not to
understand things that I actually do understand, I feel like my word
on that topic should be treated as pretty much conclusive.

I do think that you are doing some things right, for sure. But I don't
think that you are following the community process particularly well.
It doesn't really feel like you feel the need to convince other people
that your changes are in good shape before committing them; and it is
really hard for me to understand in detail what is being changed.

--
Robert Haas
EDB: http://www.enterprisedb.com