RAM advice needed

Question

I am going to install Oracle 10gR2 in an AIX machine with 15G RAM. What percentage of Physical RAM should i set aside for SGA and PGA combined. I read in the internet that it should be 80% of Total RAM size? Is this right?
During the day this oracle server will be having at least 1300 sessions(so 1300 oracle server processes running) at any given time. So, can anyone advice me of appropriate SGA_MAX and PGA_AGGREGATE_TARGET sizes.

Answer 1

Comments embedded
Thank you Syb.
The applications are run from the application server.
How would i know how much memory each application is
consuming? By measuring it on your test/acceptance server, before you go production
Why do you think Shared Server
configuration is more appropriate?
1300 processes times 8 Mb minimum, sometimes even 40 M.
Most of these processes are, from Oracle perspective, doing nothing.
Also with 1300 processes we are talking OLTP, aren't we?
The overhead of starting a dedicated process is significant.
The reason for this is your server processes needmemory too (apart from the PGA) and you should avoid
paging and swapping in normal situations
I thought PGA_AGGREGRATE_TARGET is used to control
the total amount of memory consumed by all server
processes combined. So, What do you mean by 'apart
from PGA' ?First of all there is also uga. Secondly each process needs to map the SGA into their own working set. Also there is code to run.
>
Which oracle documentation should i look to get
advice on SGA_MAX_SIZE and PGA_AGGREGATE_TARGET?You can easily search the documentation by using tahiti.
This search string provides relevant information for sga_max_size in 10g.
http://www.oracle.com/pls/db102/ranked?word=sga_max_size&remark=federated_search
But they will tell you there are no formulas and you should use the advisor.
Hth
Sybrand Bakker
Senior Oracle DBA