Re: Tuning db_block_buffer

In article <3867c445.10183372_at_super.news-ituk.to>,   See Message body for real address wrote:
>
> Is that under the same type of load and usage?
>
> The db_block_buffers hit ratio is greatly affected by how many repeat
queries
> are run as opposed to ad-hoc queries - if more users are querying the
system
> 'ad-hocly' there will not be the data they request in the buffer...
>
> mayleel_at_my-deja.com wrote:
>
> >I'm running Oracle 8.0.5 on Solaris.
> >
> >I changed the db_block_buffer from 3200 to 4800,and my hit ratio went
> >from 78-80% to 50% and dropping!!!
> >
> >Any ideas?
> >

The buffer hit ratio is an over-rated ratio. All other things being equal a decrease in the hit ratio like you saw probably means you increased the pool beyound the size where its contents are being efficiently utilized by activity. What you should really be trying to measure is does the change have any effect on the performance of the actual application.

--
Mark D. Powell -- The only advice that counts is the advice that  you follow so follow your own advice --

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Before you buy. Received on Mon Dec 27 1999 - 18:31:47 CST