CA Sysview Buffer Pool Hit Ratio on BTSTASM2

Products

• SYSVIEW Performance Management Option for DB2 for z/OS
• Database Management for DB2 for z/OS - Performance Suite
• Database Management for DB2 for z/OS - SQL Performance Suite
• Insight Performance Monitor for DB2 UDB for z/OS

Issue/Introduction

While  monitoring  DB2 Bufferpools using the CA Sysview online and batch BTSTASM2 reports, the  BP1 Buffer pool hit ratio is very low at 46.2 %

How is the Buffer pool hit ratio calculated?  From a high level it would the (total req - the total reads) / total req * 100.

 

Environment

Release : 20.0

Component : CA Insight Database Performance Monitor for DB for z/OS

Resolution

Buffer pool hit ratio in BTSTASM2 is the average not a total. You can see that definition in the BTSTASM2 in the following line:
% :041 'HIT RATIO ' AVG(BP-HITRATIO) (PF=N3.1)