Re: strange IS NULL behaviour

Bruce Momjian <bruce(at)momjian(dot)us> writes:
> On Thu, Sep 5, 2013 at 05:06:41PM -0400, Bruce Momjian wrote:
>> Another possible fix would be to avoid the IS NULL value optimizer
>> expansion if a ROW construct is inside a ROW(). I have attached a patch
>> that does this for review.

> Having received no replies, do people perfer this version of the patch
> that just punts nested ROW IS NULL testing to execQual.c?

For some reason I read your previous message as saying you were willing to
wait for considered reviews this time. If not, I'll just write a blanket
-1 for any version of this patch.

I don't think you've shown that this is more spec-compliant than what
we had before, nor that you've made all the relevant code (execQual,
eval_const_expressions, column NOT NULL constraints, plpgsql variable
NOT NULL constraints, maybe other places) mutually consistent.

I'm not a fan of incremental improvements in application-visible
semantics: if we change this repeatedly over several releases, that's an
application author's worst nightmare, because he'll have to try to work
with multiple different behaviors. We need to change this *once* and get
it right. You haven't proven that this is now right where it wasn't
before, and the patch is certainly not so obviously right that it should
go in without considered review.

regards, tom lane