--- In firebird-support@yahoogroups.com, "Ann W. Harrison" <aharrison@...> wrote:

>

>
> Primary keys are written in ascending order.
>
> For most indexes, it makes sense to reset the selectivity after
> loading records because Firebird doesn't maintain selectivity
> dynamically. For unique indexes and the indexes created to
> support unique and primary key constraints, the selectivity is
> known in advance, so you don't need to reset it.
>
>
> Good luck,
>
> Ann
>

Thanx for your answer,

but does it mean that i can't change the 'sort order' of the primary key index?
if i issue a query sorted as asc instead of desc it's instantaneous while it takes a long time to see the results when sorting desc.

maybe i should create another index including the primary key and order it desc. would that help?

is there a way to see the executing plan? i'm unable to find it in the documentation (or i might have looked in the wrong place)

kim