On Thu, Aug 5, 2010 at 9:59 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Well, if it were only a hint, and thus didn't actually "prevent"
> anything, then it wouldn't be breaking compatibility. But I don't
> like the idea much either. It would be extremely expensive, if not
> impossible, to determine whether all parents having the similarly-named
> column got it from the same common ancestor. (In particular, if the
> user had previously ignored the hint, you could have situations where
> there isn't a unique ancestor that the column can be traced to; then
> what do you do?)
>
> I think we'd be putting huge amounts of effort into a case that no more
> than one or two people would ever hit.
I don't agree that it would be a huge amount of effort, but I do agree
that only a very small number of people will ever hit it, and that it
just doesn't seem worth it. We have bigger fish to fry.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise Postgres Company