Oracle Automatic Shared Memory Management (ASMM) is a new 10g great functionality but beyond just setting the parameters in initialization parameter file you could be disappointed with what you can easily see with Grid Control.

RDBMS, Unix and many more…
When trying to get the information of redo generated per SQL statement, I came to the conclusion that there is no easy link between amount of redo generated and SQL statement as, apparently,Oracle doesn’t keep the information at statement level but only at session level (what to do if the session is persistent and never disconnect ?).
…Without Oracle Grid Control, unless would be too easy…
On very big databases segment advisor daily / week-end job is a performance killer and you normally never check the result or not more than around twice a year. So why not deactivate it and launch it manually on a small perimeter (per tablespace) and really work on the result ?