> PLAN (CUSTOMERS ORDER I_CUSTOMERS_WEIGHTEDVALUE)
> PLAN SORT (JOIN (B NATURAL,C INDEX
> (IDX_CUSTOMERS_BRANCHCODE,I_CUSTOMERS_WEIGHTEDVALUE)))
>
> Prep 0.496 sec
> Process 7.156 sec
>
> 65 non indexed reads on branches
> 160,037 indexed reads on customers

out of interest I decided to see how firebird would perform without an index
on weighted_value

PLAN SORT ((CUSTOMERS NATURAL))
PLAN SORT (JOIN (B NATURAL,C INDEX (IDX_CUSTOMERS_BRANCHCODE)))

prep 0.079 sec
process 25.312 sec

65 non indexed reads on branches
1,039,738 non-indexed reads on customers
1,035,171 indexed reads on customers

still a pretty good effort, and enough to fill me with additional love for
my favorite database

Regards
Gary