Increasing the size of the SGA

Question

I'm using the Oracle Enterprise Manager Database Control on a 10.2.0.4 instance running on Redhat Enterprise Linux. One of the recommendations that the AWR\ADDM always seems to give is: "Increase the size of the SGA by setting the parameter SGA_TARGET to N". I've gone through the process twice already by upping the SGA_MAX_SIZE and SGA_TARGET parameters. It's currently recommending to up it to 6176M, I have not done this yet.
(1) Is this one of the recommendations that you would ignore within the DBCA if performance of the database seemed acceptable?
(2) Why does it always come back from the AWR\ADDM as a recommendation?
(3) What SQL or performance statistics does it do to determine whether the SGA is undersized and how does Oracle determine the SGA recommended size that shows up in the ADDM feedback?
Thanks in advance...

Answer 1

Truely new questions do deserve new threads. Questions that are a direct result of responses to the initial question should be asked on the same thread.
If there has been a time gap between the last post on the initial thread and the new question coming to mind then a new thread is probably the better choice.
To answer the question asked if the database is not suffering ORA-04031 errors and performance is OK then I would ignore the recommendation to increase the size of the SGA yet again.
What you might want to do first is reivew how the sga is being used (v$sgastat) and look for bad code technique that leads to needing memory, i.e., the use of SQL that passes constants to Oracle in what would otherwise be the same SQL statement if a bind variable was used and excessive use of Dynamic SQL when again bind variables could have been used in the SQL.
IMHO -- Mark D Powell --