Jan Urbański <j.urbanski@students.mimuw.edu.pl> writes:
>> Tom Lane wrote:
>>> Type point has no btree opclass, no hash opclass, and not even an
>>> operator named "=" (it looks like the functionality is named ~=
>>> for some odd reason). I'd be interested to hear either a proposal of
>>> a principled way to define DISTINCT, or a way to implement it that
>>> was better than comparing every element to every other element...
> The way I see it there's nothing wrong with the definition of DISTINCT
> and for types that can't be compared there is no way of calculating
> distinct values other than comparing every element to every other.
"for types that can't be compared"? Do you not see the logical
disconnect in that sentence?
regards, tom lane