Re: AssertLog instead of Assert in some places

Hi,

On 2023-08-11 11:56:27 -0700, Peter Geoghegan wrote:
> On Fri, Aug 11, 2023 at 11:23 AM Andres Freund <andres(at)anarazel(dot)de> wrote:
> > > Couldn't you say the same thing about defensive "can't happen" ERRORs?
> > > They are essentially a form of assertion that isn't limited to
> > > assert-enabled builds.
> >
> > Yes. A lot of them I hate them with the passion of a thousand suns ;). "Oh,
> > our transaction state machinery is confused. Yes, let's just continue going
> > through the same machinery again, that'll resolve it.".
>
> I am not unsympathetic to Ashutosh's point about conventional ERRORs
> being easier to deal with when debugging your own code, during initial
> development work.

Oh, I am as well - I just don't think it's a good idea to introduce "log + error"
assertions to core postgres, because it seems very likely that they'll end up
getting used a lot.

> But that seems like a problem with the tooling in other areas.

Agreed.

> For example, dealing with core dumps left behind by the regression
> tests can be annoying.

Hm. I don't have a significant problem with that. But I can see it being
problematic. Unfortunately, short of preventing core dumps from happening,
I don't think we really can do much about that - whatever is running the tests
shouldn't have privileges to change system wide settings about where core
dumps end up etc.

> Don't you also hate it when there's a regression.diffs that just shows 20k
> lines of subtractions? Perhaps you don't -- perhaps your custom setup makes
> it quick and easy to get relevant information about what actually went
> wrong.

I do really hate that. At the very least we should switch to using
restart-after-crash by default, and not start new tests once the server has
crashed and do a waitpid(postmaster, WNOHANG) after each failing test, to see
if the reason the test failed is that the backend died.

> But it seems like that sort of thing could be easier to deal with by
> default, without using custom shell scripts or anything -- particularly for
> those of us that haven't been Postgres hackers for eons.

Yes, wholeheartedly agreed.

Greetings,

Andres Freund