select query takes 13 seconds to run with index - Mailing list pgsql-general

Hi, is there anyway this can be made faster?  id is the primary key,
and there is an index on uid..

thanks


EXPLAIN ANALYZE select * from pokes where uid = 578439028 order by id
DESC limit 6;
                                                                     QUERY PLAN

----------------------------------------------------------------------------------------------------------------------------------------------------
 Limit  (cost=0.00..9329.02 rows=6 width=135) (actual
time=13612.247..13612.247 rows=0 loops=1)
   ->  Index Scan Backward using pokes_pkey on pokes
(cost=0.00..5182270.69 rows=3333 width=135) (actual
time=13612.245..13612.245 rows=0 loops=1)
         Filter: (uid = 578439028)
 Total runtime: 13612.369 ms
(4 rows)