On Mon, 22 Mar 1999, Hearley, Jennifer wrote:
> Hi, I am not sure if you are still answering questions but if you could
> point me in the right direction I would really appreciate it. We are running
> Oracle 7.3.2 on a SunOS 5.5.1 Unix platform. The problem I have been
> encountering is as follows:
> If I reboot the server, the free memory is around 150000, however, after
> queries are performed the free memory seems to drop down to 4108 and stays
> that way till the server is rebooted. If I flush the SGA that does not
> change this. It seems as though Oracle is hanging on to the memory after the
> query is executed. And it causes the queries to run slower. Is there
> something I should be looking at to prevent.
> Thank in advance for any help you can give me.
>
> Jennifer M Hearley
> Lead Database Developer
> E-Commerce
> Newark Electronics
>
First, check if you have any packages pinned in memory. If so, that is why
your free memory does not increase after you flush the SGA.
Next, look at the V$SGASTAT view. This will tell you what is taking up
your memory.
If you are talking about system free memory (outside the database on the
server), then each connection to the database takes up memory (2-4M each
typically).
Also, information in the SGA is kept in a b-tree format. So, flushing the
shared pool gets rid of just the lowest "layer" of memory. The next flush
command removes the next-to-lowest "layer" of memory, and so on. So, to
flush out everything try:
ALTER SYSTEM FLUSH SHARED POOL;
ALTER SYSTEM FLUSH SHARED POOL;
ALTER SYSTEM FLUSH SHARED POOL;
and then check your free memory.
Best of luck,
-Ari Kaplan
Independent Oracle DBA Consultant
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