Re: Keep notnullattrs in RelOptInfo (Was part of UniqueKey patch series)

On Sun, 4 Jul 2021 at 02:08, Andy Fan <zhihui.fan1213@gmail.com> wrote:
>  I'd start to work on UniqueKey again, it would be great that we can target it
>  to PG 15. The attached patch is just for the notnull_attrs. Since we can't say
>  a column is nullable or not without saying in which resultset, so I think attaching
> it to RelOptInfo is unavoidable. Here is how my patch works.

I'd also like to see this work progress for PG15.  My current thoughts
are that Tom as mentioned another way to track nullability inside Var.
It would be a fairly big task to do that.

Tom, I'm wondering if you might get a chance to draw up a design for
what you've got in mind with this?  I assume adding a new field in
Var, but I'm drawing a few blanks on how things might work for equal()
when one Var has the field set and another does not.

David