Re: tunnig the db_block_buffer

Hello,

How did you calculate that hit rate? In 8.1.5 you should subtract the value of the 'physical reads direct' statistic from the number of 'physical reads' before calculating a hit rate. Or even better, you should calculate separate hit rates for each buffer pool from the statistics in V$BUFFER_POOL_STATISTICS. If you calculate the hit rate correctly, you may find that it is much better than you think. If not, then an increase in db_block_buffers may be indicated.

For more information of calculating the cache hit rate, please see the tip on my web site (1st URL below) on the matter.

Regards,
Steve Adams

http://www.ixora.com.au/

http://www.oreilly.com/catalog/orinternals/

http://www.christianity.com.au/

On Mon, 20 Dec 1999 18:33:32 +0200, orib_at_galileo.co.il wrote:

>Hi
>I got the following warning :
>buffer cache hit ratio : 64.6357 - may need to increase db_block_buffer.
>
>I'm running oracle 8.1.5 on sun solaris.
>Is it a meaningful warning ?
>How should I increase the db_block_buffer ?
>
>Thanks
>
Received on Tue Dec 21 1999 - 16:21:35 CST