Re: Approximately sizing SGA

On 15 Dec 2004 12:02:00 -0800, "iloadmin" <ilo_at_ilo-infosystems.us> wrote:

>Hello,
>
>I've been given the exciting responsibility of getting oracle 9 sga
>sized to be the backend of a website. I have some oracle experience
>and I understand the sga consist of memory structures which are part of
>an instance. I know the sga contain data information and manipulates
>memory virutally. My goal is to approximately size the
>shared_pool_size, db_block_size, db_cache_size and log_buffer
>parameters. After doing some research I found a formula to size the
>sga.
>
>db_cache_size + db_keep_cache_size + db_recycle_cache_size +
>DBnk_cache_size +
>shared_pool_size+ large_pool_size + java_pool_size + log_buffers + 1MB.
>
>Again, I am not trying to be exact. I do not want to accept the
>default settings of an oracle installation for these parameters. The
>database will be the backend of website and it is my first time
>attempting this. I am willing to research for all my answer and test
>my hypothesis as I learn about them so I can complete the
>responsibility. The database will be working hand in hand with redhat
>linux version 3 and the OFA for Oracle 9 have been set including the
>blocksize for the mount points.
>
>My quesiton "knowing this will be the backend what numbers should I be
>looking at to plug into these parameters to get this started" ?
>Thanks in advance,
>iloadmin

Actually, explicitly setting parameters like shared_pool_size etc will disable Oracle 9i's capability to adjust them automatically and dynamically, when there is still SGA memory available.

Also, it seems like you have choosen to use the strategy called 'hit ratio tuning', and think you can actually resolve a badly written application by throwing memory at the problem.

I think you should reconsider your strategy.

--
Sybrand Bakker, Senior Oracle DBA