priority on a process

Running PostgreSQL 7.2.1 on RedHat Linux 7.2

I have a process running and it seems that it is not
using very much of the available resources on the server
(so, if I ran 'top' to see what's running and checked the
CPU, memory and system time usage, it appears very
low).

[example]

<top>
PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME COMMAND

11467 postgres 9 0 3256 3176 2572 D 1.3 0.3 12:00 postmaster

<ps info>
postgres 11467 3.4 0.3 8204 3176 ? D 07:58 12:02 postgres:
charles testdb [local] UPDATE

<query>

update tm_wm_hedis_num_wei
set
product = b.product,
prov_num = b.prov_num
from
ref_memmonth_spans b
where
substr(tm_wm_hedis_num_wei.contract,1,9) = b.contract
and
substr(tm_wm_hedis_num_wei.mbr_num,1,2) = b.mbr_num
and
tm_wm_hedis_num_wei.date between b.effdt and b.enddt;"

[/example]

Q1: how can I move the priority of the job up so that
it can take advantage of the CPU / memory alloted?

Q2: why will some jobs hog system resouces and others,
like this one, won't do much of anything?

Thanks!

-X