Re: Indexes with descending date columns

On Fri, 2006-03-24 at 12:21, Jim C. Nasby wrote:
> On Thu, Mar 23, 2006 at 01:09:49PM +0200, Theo Kramer wrote:
> > ii If no to i, is it feasible to extend PostgreSQL to allow traversing
> >    an index in column descending and column ascending order - assuming
> >    an order by on more than one column with column order not 
> >    in the same direction and indexes existing? ... if that makes sense.
> 
> Yes.
> 
> stats=# explain select * from email_contrib order by project_id desc, id desc, date desc limit 10;
>                                                        QUERY PLAN                                                       
> ------------------------------------------------------------------------------------------------------------------------
>  Limit  (cost=0.00..31.76 rows=10 width=24)
>    ->  Index Scan Backward using email_contrib_pkey on email_contrib  (cost=0.00..427716532.18 rows=134656656 width=24)
> (2 rows)

Not quite what I mean - redo the above as follows and then see what
explain returns

explain select * from email_contrib order by project_id, id, date desc
limit 10;

-- 
Regards
Theo