Re: Busted(?) optimization in ATAddForeignKeyConstraint

On 2020-01-23 23:11, Tom Lane wrote:
> I happened to notice this comment in the logic in
> ATAddForeignKeyConstraint that tries to decide if it can skip
> revalidating a foreign-key constraint after a DDL change:
> 
>               * Since we require that all collations share the same notion of
>               * equality (which they do, because texteq reduces to bitwise
>               * equality), we don't compare collation here.
> 
> Hasn't this been broken by the introduction of nondeterministic
> collations?

I'm not very familiar with the logic in this function, but I think this 
might be okay because the foreign-key equality comparisons are done with 
the collation of the primary key, which doesn't change here AFAICT.

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services