| From: | Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> |
| Cc: | pgsql-hackers(at)lists(dot)postgresql(dot)org |
| Subject: | Re: Busted(?) optimization in ATAddForeignKeyConstraint |
| Date: | 2020-01-24 10:15:54 |
| Message-ID: | 72f98297-bd29-cee8-7195-12fa2fc40142@2ndquadrant.com |
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| Lists: | pgsql-hackers |
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
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