I have a query that behaves differently in FB 2.0 vs. 1.5. The
statement is:

select h.h_ronumber from header h
where h.h_header_id not in (select a.header_id from account_totals a)

The FB 2.0 plan is: PLAN (A NATURAL)PLAN (H NATURAL)
The FB 1.5 plan is: PLAN (A INDEX (IDX_ACCOUNT_TOTALS))PLAN (H NATURAL)

FB 1.5 takes 0.047 seconds to run and FB 2.0 takes 21 minutes to run.
It does return the exact same data.

Of course the statement is much better written as:

select h.h_ronumber from header h
where not exists(select 1 from account_totals a where a.header_id =
h.h_header_id)

Is this an intentional change in the optimizer? I do know the statement
was very poorly written whenever it was first done. It just seems that
FB 2.0 should be able to generate the same or better plan than 1.5. My
concern is only that upgrading to FB 2.0 might expose some other
'newbie' SQL code in the application that was working fine, and now
won't be.

Paul