Re: How can I tell if my SGA fits into the physical memory?

jeffyee_at_hotmail.com (Jeffrey Yee) wrote:

> Whenever I do memory tuning, I'm always worried that I might make the
> SGA memory too big, by increasing cache hit for each of the SGA
> component. Is there a definite way to tell if the SGA is fully located
> in memory? I do not have a monitoring tool on the OS level. I have
> databases running in HP, Sun and Windows platform.

The SGA will only be fully located in memory if the LOCK_SGA parameter is true.

If this requirement is not met, the operating system can (and likely will at some stage) page memory pages belonging to the SGA out to virtual (swap) memory.

To ensure that you do not make the SGA larger the available physical memory, look at V$SGA.

--
Billy