Hi!

I wonder: Was there any change in FB 2.5.4 which would slow down
processing of WHERE field IN (subselect) a lot, compared to FB 2.5.3? I
have been performing tests because a user of mine complained about slow
speed of my database, and found out that my query in the form of:

SELECT COUNT(*)
FROM a_complex_view
WHERE field1=1 AND field2<>2
AND key_field IN (SELECT key_field FROM key_field_list)

went from 2 seconds in FB 2.5.0-2.5.3 to 4 minutes in FB 2.5.4. After
rewriting the last condition to EXISTS:

SELECT COUNT(*)
FROM a_complex_view
WHERE field1=1 AND field2<>2
AND EXISTS (SELECT key_field FROM key_field_list WHERE
key_field=a_complex_view.key_field)

the speed returned to 2 seconds even in FB 2.5.4. But what could be the
cause? I went over all changes described in the 2.5.4 Release Notes and
couldn't find anything which would seem relevant.

Thanks,

Josef