Martijn van Oosterhout <kleptog@svana.org> writes:
> On Thu, Dec 29, 2005 at 04:33:32PM -0000, Andrew - Supernews wrote:
>> Does it matter? How would the same operator specify different orderings
>> in different operator classes,
> Well, we currently don't forbid it and indeed encourage it (by
> encouraging reverse operator classes) as the only way to handle the
> ORDER a, b DESC case right now.
> I don't think I can find any other examples right now. I don't think
> I'd have a problem with forbidding it at some future date.
Right, the reverse-sort opclass is the only practical example that
anyone's pointed out ... for btree. For GiST it would be a serious
error to try to restrict operators to appear in at most one opclass.
Therefore, we're not going to be forbidding it, and the code has to
behave in a sane fashion if someone does it.
regards, tom lane