Re: Postgres 9.6 scariest patch tournament

On Tue, Apr 19, 2016 at 12:37 PM, Alvaro Herrera
<alvherre(at)2ndquadrant(dot)com> wrote:
> This guy reads my mind. Where's my tinfoil hat?

Heh. Well, I'm generally not in favor of communicating concerns
without an obligation to defend them, but it could work well in tiny
doses. Offering hackers a low-risk way to take a position greatly
reduces the "knew-it-all-along" effect. We may then be more accurate
in assessing our own ability to anticipate problems.

There is very simple Malthusian logic [1] that explains why we'll
usually be wrong, which is:

Why are hackers bad at anticipating where bugs will be? Because if
they weren't, then there wouldn't be any bugs.

Please don't interpret my remarks as showing flippancy about bugs.
(The same should be said about the whole "scary patches" poll,
actually.)

>> I would have appreciated more scope to say how confident I am in my
>> prediction, and how scary in absolute terms I consider the scariest
>> patches to be.
>
> It was purposefully ambiguous. Maybe it should have been stated
> explicitely.

I voted, and my vote probably just slightly reinforced the
conventional wisdom about where to look for problems -- it was not a
vote for parallel query, since I agree with Tom's assessment of the
risks there. I think you can probably guess what I voted for.

I wouldn't have expressed a similar sentiment on this list, because
that would probably turn out to be just jumping on the bandwagon.
There is a good chance that the patch will be totally fine in the end,
anyway. It was probably very carefully reviewed, precisely because it
touches critical parts of the system. And, it works in a way that
generalizes from an existing well-tested mechanism.

My vote represented "I certainly hope this patch has no bugs in it"
this time around. Next time, it might be "this patch almost certainly
has lots of undiscovered bugs", which might well be an original
insight for the release team if it's in my area of expertise (chances
are good that those bugs are not critically important if it gets to
that). Rarely, the message will be "I'm deeply concerned about the
*lasting* repercussions of having merged this patch". And so, yes, I
think that we might want to be clearer about looking for nuances like
that.

[1] http://www.scottaaronson.com/blog/?p=418
--
Peter Geoghegan