> We have a query that is fast in the FB 2.0 RC version, but in 2.0 and
> 2.1 takes 20 minutes. Essentially it deletes all records from a table
> in a master detail relationship.
> something like delete from detailTable where not exists (select

distict

> masterTable.ID from masterTable where mastertableID = detailTable.FK)
>
> Does anyone know what might have changed significantly after that RC
> version? And will it / can it be fixed.

Try:

delete from detailTable where not exists (select 1 from masterTable
where mastertableID = detailTable.FK)