Dear Tom,
regarding the question i posted, after tests and benchmarks,
i found that retreiving the _float8 array from JDBC and doing the
calculations
in java is faster than calling a C function that performs the same
calculation
on the same _float8 array and returns float8.
In the C function there were no DB calls or any other I/O calls but plain
arithmetic,
so i declared it iscached and the benchmark loop run 1000,10000 times and
so on.
I was surprised by the result!
I am running pgsql 7.2 on a linux 2.4.7, glibc 2.2.2