Re: compute_query_id and pg_stat_statements

On Wed, May 12, 2021 at 9:03 PM Julien Rouhaud <rjuju123(at)gmail(dot)com> wrote:
>
> On Wed, May 12, 2021 at 11:33:32PM -0400, Bruce Momjian wrote:
> > How do they know to set shared_preload_libraries then? We change the
> > user API all the time, especially in GUCs, and even rename them, but for
> > some reason we don't think people using pg_stat_statements can be
> > trusted to read the release notes and change their behavior. I just
> > don't get it.
>
> I don't know what to say. So here is a summary of the complaints that I'm
> aware of:
>
> - https://www.postgresql.org/message-id/1953aec168224b95b0c962a622bef0794da6ff40.camel@moonset.ru
> That was only a couple of days after the commit just before the feature freeze,
> so it may be the less relevant complaint.
>
> - https://www.postgresql.org/message-id/CAOxo6XJEYunL71g0yD-zRzNRRqBG0Ssw-ARygy5pGRdSjK5YLQ%40mail.gmail.com
> Did a git bisect to find the commit that changed the behavior and somehow
> didn't notice the new setting
>
> - this thread, with Fuji-san saying:
>
> > I'm afraid that users may easily forget to enable compute_query_id when using
> > pg_stat_statements (because this setting was not necessary in v13 or before)
>
> - this thread, with Peter E. saying:
>
> > Now there is the additional burden of turning on this weird setting that
> > no one understands. That's a 50% increase in burden. And almost no one will
> > want to use a nondefault setting. pg_stat_statements is pretty popular. I
> > think leaving in this requirement will lead to widespread confusion and
> > complaints.
>
> - this thread, with Pavel saying:
>
> > Until now, the pg_stat_statements was zero-config. So the change is not user
> > friendly.
>
> So it's a mix of "it's changing something that didn't change in a long time"
> and "it's adding extra footgun and/or burden as it's not doing by default what
> the majority of users will want", with an overwhelming majority of people
> supporting the "we don't want that extra burden".

For what it's worth, I don't think the actual changing of an extra
setting is that big a burden: it's the figuring out that you need to
change it, and how you should configure it, that is the problem.
Especially since all major search engines still seem to return 9.4 (!)
documentation as the first hit for a "pg_stat_statements" search. The
common case (installing pg_stat_statements but not tweaking query id
generation) should be simple.