Let’s start this discussion candidly – I am a big fan of the FETCH FIRST n ROWS ONLY clause coded in a SQL statement. That assertion will require some clarification, since there are some valid use cases, and others that make little sense. Regardless, I will try not to over-complicate the...
by David Simpson & Linda Claussen There has been quite a bit of attention paid to the access path stability features of DB2 for z/OS since they first appeared in DB2 9. Enhancements have followed in each subsequent release. This article will discuss these features. A very common use...
Hi! I cobbled together a little SQL to create a cross-reference of all DB2 tablespace, tables and indexes with key columns, uniqueness etc. I use it all the time and I finally got around to making it recursive as well. Tested in all available releases of DB2 Roy
sysselix.txt
Selectivity Overrides – Fixing Your Filter Factor Problems By Joe Geller Scenario – your query is performing poorly. Checking an Explain, you see DB2 picked an access path which you think is less than optimal. First, you make sure there are appropriate indexes. Then you look to see...
By Kurt Struyf, Lone Star Consulting This article is based on a recent tuning engagement at a customer site and describes the countermeasures that were enacted to restore system performance. Those countermeasures include a daily process to establish an access path baseline and sample jobs...
In this comprehensive overview of DB2 10 for z/OS, Lori Ann Galluzzo goes through the features of DB2 10 in great detail. Each feature is discussed, along with how and when to take advantage of the feature, as well as some pitfalls and things to watch out for. This IDUG Tech talk video (as...
I was the conference chair for IDUG North America in Anaheim, CA in 2011. During the opening session I had the privilege of honoring Roger Miller and his contributions to DB2 and IDUG as it would be Roger’s last IDUG conference before his retirement. We presented Roger with a crystal globe...
As DB2 reaches its 30 th anniversary and IDUG reaches its 25 th anniversary, I’ve thought about many DB2 tips and best practices that have been incorporated by companies, projects and applications that have led to great successes. The ones that have been most common and have had the greatest...
DATE: 2010-5-14 (11:00 AM - 12:00 PM) SPEAKERS: Suresh Sane (DST Systems Inc) In a DB2 production environment, almost all software changes are Typically tightly controlled, but the impact of production binds and rebinds is not. This can result in unpredictable performance since it must be dealt...
NA10A15.pdf
DATE: 2010-5-14 (08:30 AM - 09:30 AM) SPEAKERS: Alexander Kopac (Home Depot) The DB2 LUW Design Advisor is cool tool designed to help define suitable indexes and for testing SQL workloads. Here's a presentation that covers both the command line syntax basics and the GUI approach for making both...
NA10D13.pdf