Re: Defining a foreign key with a duplicate column is broken

David Rowley <dgrowleyml@gmail.com> writes:
> On Sat, Aug 9, 2014 at 12:13 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> So I'm thinking you're right: we should rewrite this code so that only
>> indexes having all columns distinct can match, thereby ensuring that there
>> is only one possible interpretation of the equality semantics for the
>> foreign key.

> I've attached a patch which disallows these, though I was not quite sure
> about the new error message since likely this is something that should be
> backpacked? I wasn't sure on the policy for new translations in a minor
> release.

There's no need for a new error message I think, because we should just
ignore such indexes.  After all, there might be a valid matching index
later on.
        regards, tom lane