sir's / madam's
need advice

How can you check if what kind of server sertup is my
Oracle Database ? if dedicated or shared ? can i changed the
setup?

and whats the best setup for an OLTP type of database
which has at max of 250 users with 500 sessions...???
but its not always 250 users who are loged in -- it may be
below 50 users at a instance also...

shared or dedicated...?
8 G of RAM my setup (shared - i think)
SGA
shared pool ? 2Gig
buffer cache ? 856MB
large pool ? 1.2Gig
java pool ? 0 - since we dont use JAVA for this
PGA ? 2 Gig


thanks...