Many thanks for the detailed reply and explanations, Helen!

> You have hit the nail right on the head there! Don't try to fix something if it aint broke! ;-)

This indeed wouldn't make sense :-) I've tried that based on the mainly wrong assumption / information about query plans, which your reply shows pretty well.

> This topic is right off-topic for IBO...so if you need some advice about cleaning up and maintaining indexes, ask in firebird-support (unless you are using InterBase, in which case ask in the appropriate Embarcadero forum).

Wasn't sure where to post. firebird-support would have been better probably, but since I thought that there is a need for predefined plans and hoped that there is a way to generate one, I've posted here as it would have to be done with IBO in such a case, I think. But well, all this is irrelevant now, because there is no need to do so.

This part made me pondering though: "so if you need some advice about cleaning up and maintaining indexes, ask in firebird-support". My indexes are most likely not perfect, but no idea what / how to ask regarding cleaning up and maintaining indexes... Will have to think about it, but that's certainly a case for firebird-support.

Thanks,
Patrick