Top command on Solaris

I type 'top' in solaris and see many processes running:


PID USERNAME THR PRI NICE SIZE RES STATE TIME CPU COMMAND
20408 oratst 1 52 0 190M 171M sleep 0:02 2.35% oracle
20410 oratst 1 54 0 190M 171M sleep 0:02 1.14% oracle
20480 root 1 0 0 2320K 1288K cpu/1 0:00 0.60% top
20479 oratst 1 0 0 30M 9232K sleep 0:00 0.31% oracle
20477 oratst 1 0 0 30M 9232K sleep 0:00 0.23% oracle
20471 oratst 1 0 0 30M 9232K sleep 0:00 0.18% oracle
20473 oratst 1 0 0 30M 9232K sleep 0:00 0.17% oracle

Should I be worried about what 190M is as a size, given that there are several hundred of these processes - it sounds like a lot of memory being used - how can I change this?

Thanks
Raj