Re: pg_plan_advice

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> ... But I also feel like if we've only seen one buildfarm
> failure since the last round of stabilization, it might not be a
> catastrophe if nothing further is done before feature freeze. In fact,
> I think it might be *good*. Given the apparently-low failure rate that
> we now have, it feels to me like we might want to run like this for a
> month or even or two or three to get a clearer feeling for whether the
> failure you saw is the only one or whether, perhaps, there are others.
> Or even just how often this one happens.

Reasonable point.

> I mean, there is possibly an argument that we don't really need to
> gather any more information about the problem; it does seem like we
> understand what is going on here, and if we had a great, simple fix I
> would probably just apply it and be done with it. But I also don't
> quite understand why you're in such a rush. If we still feel like
> running the tests serially is the best solution in a month, can't we
> just do it then?

The terms that I'm thinking in are "how much redesign will we accept
post-feature-freeze, in either pg_plan_advice or test_plan_advice,
before choosing to revert those modules entirely for v19?". I think
that running those tests serially is a sufficiently low-risk option
that it'd be okay to put it in post-freeze, even very long after.
I'm not sure that any of the other group-1 or group-2 options you
suggested would be okay post-freeze. (Of course, ultimately that'd
be the RMT's decision not mine.)

I believe that we probably will need to do something in this
area before v19 release. If we're willing to commit to it being
"run the tests serially", then sure we can wait awhile before
actually doing that. Maybe we'll even think of a better idea
... but what we can do about this post-freeze seems pretty
constrained to me.

regards, tom lane