Server: Dell server, 50GB physical memory
OS: Windows 2012 R2
DB: Oracle 11g R2 Standard Edition One/Two
When we install Oracle db, by default it will assign 40% of physical memory to Oracle database. So assuming it will assign 20GB to Oracle DB. Now if we setup the Oracle DB in AMM (automatic memory management) mode.
memory_max_target=20G
memory_target=20GB
sga_max_size=20G
sga_target=0
pga_aggregate_target=0
Hoping if all my parameters above are correct, we have allocated 20GB memory for Oracle DB on this server.
When we start the server, initially Oracle.exe process (windows task manager) might show up only 3GB used and later during peak hours it can go to a max of 20GB max. correct ?
Now even though I allocated 20GB for Oracle db, where can we check and see what is the max memory Oracle db has used so far ? ( from last instance reboot - or from day one when the db was installed).
I'm hoping looking at the HWM(highwatermark) would show the max memory db has used so far. Lets assume that it shows 20GB HWM. Does it mean that Oracle db used 100% of allocated memory(20GB) at some point-in-time ?
Now at this point if we wanted to see if allocating more memory to Oracle db would help or not. If we run a statspack report for last month and the instance efficiency shows 99% for most of the memory pools. Does it mean we don't need to allocate more memory to oracle db ?
(or)
Lets say if we now allocate 30GB to Oracle db (AMM). And after 3 months it show HWM as 30GB. Does it mean that Oracle used 30GB as well at some peak hours ?
Correct me if I'm wrong. Thanks in advance.