Re: Memory limitations in Oracle?

Vikas Agnihotri <vikasa_at_despammed.com> wrote:
>Are there any memory limitations in Oracle?
>
>In other words, if I have a machine with 20GB of physical memory
>(hypothetically), can I assign it all to Oracle's SGA via the relevant
>instance parameters (db_block_buffers, shared_pool_size, log_buffers,
>etc).

I'm currently running an instance with a 20GB SGA. Whether you'll be able to or not depends on your OS and the version of Oracle. Things claiming "64 bit" are usually a good bet.

Even if your OS and Oracle version support large SGAs, you may need to ensure that your OS is configured to do so. Things like maximum size of shared memory segments, and maximum number of shared memory segments are important.

Oracle will refuse to start unless it can allocate all memory without paging to disk. However, allocating all your RAM to Oracle's SGA is probably an unwise decision, what are the Oracle shadow processes going to use, let alone any other process you might want to run?

>On a related note, what is the new large_pool_size parameter in Oracle
>8i?

This is best answered by reading the documentation, it's not an underscore prefixed parameter, so it's documented. Briefly, don't worry unless you're running MTS.

-- 
Andrew Mobbs - http://www.chiark.greenend.org.uk/~andrewm/