Top resource intensive processes on AIX/Unix/Linux

Question

top is good to find this out, topas on aix, any other tips to find out memory/IO resource intensive processes, here i have for cpu....
oracle:tulpfsd01$ ps -e -o pcpu -o pid -o user -o args | sort -k 1 | tail -5r
%CPU PID USER COMMAND
1.1 1230914 oracle oraclepwpd (LOCAL=NO)
0.9 1248744 oracle oraclepwpd (LOCAL=NO)
0.9 1099146 oracle oraclepwpd (LOCAL=NO)
0.6 503688 oracle oraclepwpd (LOCAL=NO)
0.5 1239486 oracle oraclepwpd (LOCAL=NO)

Answer 1

Generally, memory shouldn't be a concern. The total amount of SGA is set (fixed) with SGA_MAX_SIZE and occupies shared memory (to be seen with 'ipcs')
The PGA is set by PGA_AGGREGATE_TARGET, but is only a rough pointer for oracle. Additional information about memory is seeable with pmap (alt least on linux and solaris)
You'll see the loaded shared libraries (which are used by the process in a shared matter, so not any process which uses libraries copy their own versions, and you should be able to identify the shared memory (identified with shmid=0xsomething) etc. On linux /proc/<pid>/maps shows the same in a little different way.
Now we've established that the shared libraries are used shared to preserve memory, and the shared memory is used shared (quite obviously), and 'put' into the process' address space, you should understand why listing VSS (virtual set size) and other memory stuff isn't very helpful: if you just add all listed used memory, there are much components which are not really used by that process.
Top and topas are helpful for finding CPU intensive processes. That is what both are designed for, to be able to identify the processes which are using the most slices of processor time. Of course, it's only helpful if you truly want to identify top CPU intensive processes. This is also quite easy to find inside the database.
IO: there's no way to identify processes which are the most intensive writers. Simple because linux doesn't keep statistics about it. Inside the database, it's easy to find (guess you should need an example of that?) please mind you should be aware how the database works: a user process does no writing, it's the logwriter, checkpointer and database writer who does that. The user process only reads.
I will see if I can find some nmon examples tomorrow, when I've got access to AIX systems.
If you still want examples, could you be specific?