Re: Functional dependencies and GROUP BY

On fre, 2010-07-23 at 11:00 -0600, Alex Hunsaker wrote:
> I just read that patch is getting pushed till at least the next commit
> fest: http://archives.postgresql.org/pgsql-hackers/2010-07/msg01219.php
>
> Should we push this patch back to? Alternatively we could make it
> work with just primary keys until the other patch gets in. I think
> that makes sense, find that attached. Thoughts?

I was thinking the same thing.

> Note I axed the index not null attribute checking, I have not thought
> to deeply about it other than if its a primary key it cant have non
> null attributes.... Right? I may have missed something subtle hence
> the heads up.

Another open question I thought of was whether we should put the
dependency record on the pg_index row, or the pg_constraint row, or
perhaps the pg_class row. Right now, it is using pg_index, because that
was easiest to code up, but I suspect that once we have not-null
constraints in pg_constraint, it will be more consistent to make all
dependencies go against pg_constraint rather than a mix of several
catalogs.