Hi Folks,

My system: DB2 v9.5_FP0 (Wintel),

I have database with poor performance. After performing some investigation I found the following:

The Synchronous Read Percentage (SRP) is 25.4.
using SQL:
SELECT SUBSTR(A.DB_NAME,1,10) as DBNAME,
CAST(( 100.0 - ((A.POOL_ASYNC_DATA_READS + A.POOL_ASYNC_INDEX_READS + A.POOL_ASYNC_XDA_READS) * 100.0)
/ (A.POOL_DATA_P_READS + A.POOL_INDEX_P_READS + A.POOL_XDA_P_READS + 0.01))
AS DECIMAL(5,2)) AS SRP,
A.DBPARTITIONNUM AS PART
FROM sysibmadm.SNAPDB A
ORDER BY A.DBPARTITIONNUM;

What could I do to increase the SRP?
Bufferpool hit ratio was 71%, so I increased the size of the BP.

Thanking you in advance.

ur BP should be always 99% for better performace i believe u can chk the page clearners and page fetchers parameter , chgpage threshold and db2 register variable
DB2_USE_ALTERNATE_PAGE_CLEANING
regds
Paul

Did you look at the numblockpages and blocksize in the bufferpooldefinitions? (DBI Blogs :: General :: DB2 LUW Performance: NUMBLOCKPAGES and APPR)
and... it is a database, so (by definitions) it is hungry for memory: FEED IT!

HI,

Thanks for your replies.

* I set NUMBLOCKPAGES to be 3% of BP(s)
* DB2_USE_ALTERNATE_PAGE_CLEANING=ON
* Increased NUM_IOCLEANERS by

which has improved perfromance.

Looking further into the problem I have noticed excessive leaf page scans & data page scans. So will look into defining/improving more precise indexes.

Thanks.

You should install the latest fixpack. Only a masochist would use FP0 of any release. If this is Express-C, you can get 9.7.2.