Michigan Db2 Users Group – December 2017

MDUG – Michigan Db2 Users Group

December 6th, 2017

SEGUS & SOFTWARE ENGINEERING present

1- 25 Years of Missed Opportunities? SQL Tuning Revisited

2- Db2 z/OS Lies, Damn Lies, and Statistics

1- 25 Years of Missed Opportunities? SQL Tuning Revisited

“But that’s the way we’ve always done SQL Tuning” – sound familiar?

The definition of madness is to keep doing the same thing and expecting a different outcome.
Find out how to stop the madness.

“Nothing is more expensive than a missed opportunity” (H. Jackson Brown, Jr).

This is especially true when it comes to SQL Tuning!

There are many low-hanging fruits within easy grasp of anyone tasked with tuning their systems. But how do you know what is dangling within reach if you can’t see it?

Find out how a modern DB2 z/OS SQL warehouse can collect and store all executed static and dynamic SQL (plex-wide) with basically no overhead.

By comparing SQL statements side-by-side, the “easy pickings” will immediately become apparent. But why stop there? Experts can effortlessly dig deeper and find the totally hidden gems: Disc Problem Detection, Delay Detection, Never executed SQL, SQL Timeline. Precisely pinpoint specific areas to target and get the most out of your DB2 system – while reducing costs.

Outlines

1 – Tuning SQL – how we always done it

2 – Single SQL, package, application

3 – Tuning SQL – year 2004 – ACCESS PATH comparison and simulation

4 – Tuning SQL Revisited – A new methodology

5 – Harvesting the low hanging fruit

2- Db2 z/OS Lies, Damn Lies, and Statistics

..Lies, damn lies, and statistics… – Benjamin Disraeli, Prime Minister of England (1868, 1874-1880)

The above line may, or may not, have been spoken well over 100 years ago, but the need for statistics and, above all else, accurate statistics is more important than ever in the Db2 world of today.

Presentation Outline

• Db2 RUNSTATS basics & catalog tables and Columns used for access path
• IBM recommendations through the ages : from Db2 V3 to Db2 12
• Db2 RUNSTATS advanced
• SYSCOLDIST explained
• RUNSTATS real world Q&A :
  use of SAMPLE, COLGROUP, PROFILE, REOPT (ONCE), TABLESAMPLE SYSTEM, HISTOGRAM, …
• RUNSTATS reversal

Speaker Biography

Ulf Heinrich is the Director of Solutions Delivery at SOFTWARE ENGINEERING GmbH. He specializes in Db2 recovery issues and database maintenance, focusing on the growing requirement for cost reduction and 24×7 operations. As a consultant at large customer sites, he has implemented database maintenance procedures and recovery strategies, and also experienced the pitfalls of recovery scenarios under real‐world recovery pressure. His activities cover EMEA, as well as North America through SE’ U.S. subsidiary, SEGUS Inc. He’s involved in the development of SE’ maintenance and recovery Solutions.