On Sat, Dec 04, 2010 at 12:19:59PM -0500, Tom Lane wrote:
> Andrew Dunstan <andrew@dunslane.net> writes:
> > Those are difficulties, certainly. Are they insurmountable
> > obstacles, though? This is something that has been on the TODO
> > list for ages and I think is very worth doing, if we can.
>
> They're possibly surmountable with enough effort, though I think in
> reality what you'd end up with is annoying corner-case behaviors
> (eg, deadlock failures in some cases). Anyway Greg and I seem to
> agree on the bottom line: such a feature is not actually interesting
> for partitioned tables, as it destroys most of the benefits of
> partitioning. I have a feeling that the feature will languish on
> the TODO list forever, unless someone comes up with a brilliant idea
> to avoid the problems. As is, the return on investment to do it
> just isn't there.
If we can teach the database things like, "the foo and bar columns are
guaranteed never to overlap among the partitions," it should be
possible make uniqueness guarantees over sets of partitions without
using a common index.
Cheers,
David.
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