Proactive Index Design using QUBECourtesy of Tapio Lahdenmäki

Lauri PietarinenRelational Consulting

Session Code: F04Nov 09, 2010 8:30 – 9:30 AM | Platform: z/OS, LUW

2

Q - Quick U - Upper B - Bound E - Estimate

A simple formula for estimating CPU and elapsed time for queries,created by Tapio Lahdenmäki and others at IBM-Finland

Basic Access Methods

Simple Anatomy of the B-Tree Index

Recommended Mental Image

Case Study: Request Tracking

Common Transaction

Which One is Faster?

Sequential Read in 2010

Random Read in 2010

Random Read from Disk Drive

Disk Drives – the Bottleneck

Quick Upper Bound Estimate (QUBE)

Alternative 1

Alternative 2A

Alternative 2B

The Basic Question

Semi-Fat Index

QUBE for Semi-Fat Index – Your Turn!

Still Too Long – What Next?

When Do Touches Take Place?

No Sort, 20 Fetches

Worst-Input Estimates

Fat Index with Sort

Worst-Input Estimates, with Fat Index

Too Expensive?

The Cost of Adding an Index

The Cost of Adding an Index Column

So, Too Expensive?

Obsolete and Relevant Guidelines

Index BO was not Adequate for this Select

QUBE for Semi-Fat Index -- Solution

SummaryQube is a way

of thinking about indexes

It can be used to prevent

performance problems

It can (and should) be

used in conjunction with other

tools

It can be used to understand and analyze performance

problems

Lauri PietarinenRelational Consultinglauri.pietarinen@relational-consulting.comF04Proactive Index Design using QUBE