Re: using index or check in ALTER TABLE SET NOT NULL

On 2018-Nov-13, Dmitry Dolgov wrote:

> > On Sun, 4 Nov 2018 at 19:03, Sergei Kornilov <sk(at)zsrv(dot)org> wrote:
> >
> > > If not properly cataloguing NOT NULL constraints would be fixed, can it
> > > potentially conflict with the current patch or not?
> > We already doing same stuff for "alter table attach partition" and in this patch i use exactly this routine. If proper cataloguing would conflict with my patch - it would conflict with "attach partition" validation too.
> > I think proper cataloguing can be implemented without conflict with proposed feature.
>
> Yes, indeed, this patch relies on the PartConstraintImpliedByRelConstraint.
> Then maybe it makes sense to go with the solution, proposed in this thread,
> while leaving open the possibility of having "SET NOT NULL NOT VALID"? From
> the functionality point of view it definitely would be beneficial. Any other
> opinions?

I think we should ignore any SET NOT NULL NOT VALID patches, because
in practice they don't exist. Let's move forward with this, because the
optimization being proposed is clearly very useful.

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Álvaro Herrera https://www.2ndQuadrant.com/
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