On Wed, 30 Sep 2020 at 11:43, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> Alvaro Herrera <alvherre@2ndquadrant.com> writes:
> > On 2020-Sep-29, Tom Lane wrote:
> >> Meh. If you've read that bit you probably already understand that
> >> pkeys are unique constraints. I think the problem is with the error
> >> text not the docs.
>
> > Maybe mention PKs in parens:
>
> > "Unique constraints (and[, by extension,] primary key constraints) on
> > partitioned tables must include all the partition key columns. This
> > limitation exists because PostgreSQL can only enforce uniqueness in each
> > partition individually.".
>
> I don't object to clarifying that (and that wording seems fine), but I
> think fixing the error message is more important. We'd not be having this
> discussion if the OP had found that documentation.
I do agree the error message is the first thing we should be changing.
I'll write a doc patch if you handle the error message.
David