Re: Reverse-sort indexes and NULLS FIRST/LAST sorting

Tom Lane wrote:
> Heikki Linnakangas <heikki(at)enterprisedb(dot)com> writes:
>> I'd like to see this implemented with more general collation support in
>> mind.
>
> I'm really not prepared to buy into that, simply because it puts ICU or
> some equivalent large chunk of new code into the critical path to finish
> what I'm doing. ...

Yeah, I didn't mean doing that right now. Just to keep it in mind so
that what we do now fits in nicely with it in the future.

>> The NULLS FIRST/LAST support, as well as ascending and descending
>> orderings would be special cases of the general collation and collation
>> conversion machinery.
>
> That seems like a bad idea, because nulls first/last and asc/desc
> ordering are valid concepts for all btree-indexable datatypes, whereas
> collation is only meaningful for text. Besides, that approach just
> moves the bloat over from too-many-opclasses to too-many-collations; do
> we really want to need four collation objects for each basic collation?

Hmm, I guess we don't.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com