Re: [PATCH] pg_stat_activity: make slow/hanging authentication more visible

On Wed, Sep 11, 2024 at 09:00:33AM -0400, Robert Haas wrote:
> On Tue, Sep 10, 2024 at 4:58 PM Noah Misch <noah(at)leadboat(dot)com> wrote:
> > ... a rule of "each wait event appears in one
> > pgstat_report_wait_start()" would be a rule I don't want.
>
> As the original committer of the wait event stuff, I intended for the
> rule that you do not want to be the actual rule. However, I see that I
> didn't spell that out anywhere in the commit message, or the commit
> itself.
>
> > I see this level of fine-grained naming
> > as making the event name a sort of stable proxy for FILE:LINE. I'd value
> > exposing such a proxy, all else being equal, but I don't think wait event
> > names like AuthLdapBindLdapbinddn/AuthLdapBindUser are the right way. Wait
> > event names should be more independent of today's code-level details.
>
> I don't agree with that. One of the most difficult parts of supporting
> PostgreSQL, in my experience, is that it's often very difficult to
> find out what has gone wrong when a system starts behaving badly. It
> is often necessary to ask customers to install a debugger and do stuff
> with it, or give them an instrumented build, in order to determine the
> root cause of a problem that in some cases is not even particularly
> complicated. While needing to refer to specific source code details
> may not be a common experience for the typical end user, it is
> extremely common for me. This problem commonly arises with error
> messages

That is a problem. Half the time, error verbosity doesn't disambiguate enough
for me, and I need backtrace_functions. I now find it hard to believe how
long we coped without backtrace_functions.

I withdraw the objection to "each wait event appears in one
pgstat_report_wait_start()".