IN optimization in 7.2 ?????

hi
was there optimization for IN (SELECT ... ) usage in 7.2?
we just got query which runs 7 times as fast with in than with exists !
the query is like select field from table where id in (select ... where
 fieldx in (... IN (...)));

depesz

--
hubert depesz lubaczewski                          http://www.depesz.pl/
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