having and union in v7beta

I'm comparing v6.5.2 against v7.0 and I see now:
UPDATEs and INSERTs are faster in v7.0 than v5.6.2 but
SELECTs are slow, specially:
SELECT ... UNION (is 3 / 4 times slow)
and
SELECT...HAVING, this last for example doesn't work.

I'm waiting for hours to have the result of following query:

EXPLAIN select * from comuni where nome in
(select nome from comuni group by nome having 1 < count(nome));

Seq Scan on comuni (cost=0.00..3429753.65 rows=8342 width=84)
SubPlan
-> Aggregate (cost=0.00..822.22 rows=834 width=12)
-> Group (cost=0.00..801.37 rows=8342 width=12)
-> Index Scan using knome on comuni (cost=0.00..780.51
rows=8)

EXPLAIN

--
Jose' Soares
Bologna, Italy Jose(at)sferacarta(dot)com