DB2® Universal Database for OS/390® Version 7.1 Certification Guide

Buffer Pool and Subsystem Tuning

Here we will discuss some of the performance aspects of some of these areas in DB2 memory. For more details on these objects refer to Chapter 2, Environment.

Buffer Pools

Separation

Buffer pools need to be fine-tuned for best performance. They work best when the data in them has like characteristics so that the thresholds for the write operations and queue management may be tuned according to the behavior or the applications against the data.

Thresholds

There are several thresholds used for buffer pool tuning. They can be different for each buffer pool. The following is a list of thresholds:

• VPSEQT— sequential steal threshold

• DWQT— deferred write threshold

• VDWQT— vertical deferred write threshold

• VPPSEQT— parallel ...