Author: Ember Crooks

2

Detailed Analysis of Individual Performance Metrics

Sometimes the things we studied in college are actually useful. As much as I hated my statistics professor, I still learned a lot that I frequently use. Maybe I don’t do many multiple regression problems these days, but I use standard deviation a lot. It is a concept that every DBA or really any IT professional who must analyze performance...

3

The Danger of FETCH FIRST ROW ONLY

There are a a vast array of things you can do in SQL. But just because you can doesn’t always mean that you should. I recently ran into an interesting situation with FETCH FIRST ROW ONLY. How the Problem Manifested The day after new code was deployed, a production database system that usually runs with 40% CPU utilization or less...

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Activities vs. Requests

This started as a conversation with a couple of DBA friends when we were playing with MONREPORT.DBSUMMARY. That’s a pretty nifty way to get a quick look at a number of performance parameters, AND to limit the time period covered by the report. But the thing we noticed and were talking about is the difference between activities and requests. In...

1

DB2’s Got Talent 2014

One of the highlights of 2013 for me was winning third place in the DB2’s Got Talent competition. If you’re a long time reader, you may remember me begging for votes the last two years in March. But this contest is for those who are newer to presenting about DB2 topics in the larger DB2 community, so I’m done –...

2

2013 Year in Review

My Year I first want to share a few things that stood out this year. In March, I won third place and a free iPad in the DB2’s Got Talent show. I highly recommend participating – great way to hone your presentation skills and to get your name out there in the DB2 community. The 2014 show is looking for...

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Care and Feeding of Statistical Views

The whole point of statistical views is to improve the performance of SQL that joins tables. Or to help you collect statistics on expressions – though if you’ve got 10.5, consider expression-based indexes for that instead. Giving the DB2 Optimizer more data is generally a good thing for query performance. If you don’t keep runstats current on your statistical views,...

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DB2 Night Show EggNog Party on Friday!

Come listen to the Third Annual DB2 Night Show EggNog Party at 10 AM CT on December 20th(tomorrow!). I’ll be one of the guests! This is a fun annual tradition. It’s near Scott’s birthday, and he occasionally gives out birthday presents to his live audience! It is also fun to hear DB2 folks you’ve heard of share their views of...

5

Using a Statistical View to Improve Query Performance

Sometimes just using the index advisor and a bit of common sense, you can address SQL performance issues. But other times, you have to dig a bit deeper. I recently found the following query and 300 of its closest cousins (differing only in the length of the second in-list) were eating 30% of the CPU time used by queries on...