Re: AIX 4.2 and Oracle 7.2/7.3 SGA/PGA and virtual memory

Anton Dischner wrote:
>
> Hi,
>
> i did performance measurements with different SGA sizes on different
> CPUs.
>
> IBM RS6000 5xx and SMP, SGI, HP. Oracle 7.x
>
> I found that a small SGA performs better than a big SGA !!
> I believe this is because filesystem caching performs better than
> Oracle SGA-caching.
>
> Give a small SGA a try!
> Make Oracle-blocksize as big as possible.
>
> Kind regards,
>
> Toni
>
> --
> A. Dischner, SGI&AIX sysadmin, Oracle DBA | Don't let friends
> Institut fuer Klinische Chemie | use WinDose
> Klinikum Grosshadern | Just say NO.
> Ludwig Maximilians Universitaet Muenchen, GER |
> Marchioninistr.15 81366 Muenchen 49-89-70953202 |

This surprises me a lot!!!!

I thought that because Oracle is able to distinquish between which reads are likely to be reused (lru-algorithms, indexed reads etc.), it would be a benefit to give the ram to Oracle.

I am presently increasing the sga (db_block_buffers, shared_pool_size) and has decided to test the users view on performance by reverting to the previous settings for a few days.

I will report what the users believe (ram to AIX or Oracle).

Regards

Jens Wartenberg
Wartenberg Industri Data
Denmark Received on Fri Mar 07 1997 - 00:00:00 CST