Indexen on 8.0.3

Hi,

After upgrading to 8.0.3 I see very poor performance on several indexes.
Like this: (udps is a view on main)

palga=> explain analyze select rapnaam from udps where naamvrouw like 'vos%';
                                                     QUERY PLAN
--------------------------------------------------------------------------------------------------------------------
 Index Scan using nv on main  (cost=0.00..242.65 rows=60 width=14) (actual
time=6.475..11598.502 rows=5692 loops=1)
   Index Cond: (((naamvrouw)::text >= 'vos'::character varying) AND
((naamvrouw)::text < 'vot'::character varying))
   Filter: ((naamvrouw)::text ~~ 'vos%'::text)
 Total runtime: 11606.250 ms
(4 rows)

The index was created with:
CREATE INDEX nv ON main USING btree (naamvrouw);

Database was recently analyzed. Clearly, something has to be tuned that didn't
need tuning on 7.4.3 ? (Main table has about 1.7 million records).

Any suggestions welcome.

Cheers,

Han Holl