ST04 Data buffer quality Less than 65%

[Former Member]

Hi,

In ST04 Data buffer quality shows below 65%.Can i increase the Database buffer size? its 4,014,080 KB right now.Is there anything else that i need to check ( We are on Solaris and Oracle)

Thanks

Prince

[Former Member]

We have a simimar issue, here is what we have reported to SAP.

We have noticed that under ST04 our Data Buffer quality is down to 82.3

%.

Here is our environment details:

- SAP R/3 Kernel 46D

- Database library OCI_816_64

- SunOS 5.7 Generic_106541-05 sun4u

- SAP 4.6c

- Kernel 4.6d

- Oracle - 9.0.2.6

Our Oracle db_block_buffer parameter is set to 4000000. Our concern is

based on the oracle note below:

"Buffer Cache Hit Rate Buffer Cache Hit Ratio is dependent upon RDBMS

size, SGA size and the types of application being processed. It is the

percentage of logical reads from the SGA as opposed to total reads -

the figure should be as high as possible. Any hit ratio less than 95

percent for an OLTP environment or 85 percent for batch application

should be investigated. The hit ratio can be raised by increasing

DB_BLOCK_BUFFERS initialization parameter, which increases SGA size.

Buffer Cache Hit Rate 85.18"

We have looked at note 617416 - Oracle9i: Dynamic SGA for SGA setup and

we don't have any of the parameter set in the SAP profile for SGA.

The question we have is:

1. Should we be concerned about the low percentage of the Data

Quality Buffer

2. What is the recommendation from you to improve the quality.

3. Also, are we in a position to setup the SGA in our environment

I was wondering if you had any reponse on the SDN site.

Ali

[Former Member]

Hi Ali,

8.3% is not that good. You can try using the dynamic SGA feture of oracle 9i. You have already looked into the note 617414. Set upper limit for SGA ( sga_max_size) and set db_cache_size , this enables the dynamic SGA.If its enabled you can dynamically change the db_cache_values if db buffer quality seems poor. db_block_buffer become obsolete if dynamic SGA is ebabled.

Thanks

Prince

Message was edited by: Prince Jose