Database performance is heavily influenced by data volume and cardinality (or how unique that data may be). It’s interesting to watch the look on someone’s face when this concept clicks. There is a look of understanding from a developer when…
“Relational databases don’t scale!”. This is the claim that database experts have heard over and over again, and yet we spend our careers scaling databases. I immediately translate this in my head to either “I threw hardware at the problem…
Edited 12/13/2017 to correct image and details about the database heap. Db2 memory management is a complex topic that I’ve already written about from several perspectives, and have a few blog entries in mind to explore further. A presentation that…
The Problem I often lean on analogies when I speak to non-technical people about technical topics. For example, I would explain database locking as “two kids fighting for the same candy bar”. If you introduce isolation levels into the conversation,…
While I have tuned backup performance before, it has often been through physical database changes (spreading tables across more table spaces) that I achieve my greatest results. This post is not about backup performance tuning, but about solving a specific…
Some of the more complicated work a DBA does is often analyzing a query. Whether it is proactive or in response to a performance problem, there are so many factors that go into query performance. Even when looking at a…
I think that one of my least favorite phrases is “Nothing else changed!” More common than a performance problem that simply slowly creeps up with performance getting worse and worse over time is the sudden performance problem. Many times, sudden…
I have some very specific perspectives on monitoring DB2. In addition to regular consulting in my day job, we also provide full-service virtual DBA services, including monitoring. The monitoring we choose to do is very much under my control, and…
dsmtop is a long-awaited refresh of the wildly popular db2top. Like db2top, dsmtop is a free tool, included with DB2. It is in the base DB2 install starting with 11.1, and can be installed on DB2 10.1 or 10.5. History…
I am consistently shocked and appalled at how few clients actually do load testing. Many pay it lip service, but few actually engage in real, meaningful performance and load testing. I understand that load testing of an application can be…
A number of new clients I’ve worked with lately have had minor or major runstats or reorg issues. I have tons of advice on runstats and reorgs across many blog entries, but I don’t have one place where all that…
The package cache is just one memory area that DB2 offers to tune memory usage for a DB2 database. This article is a deep dive into this memory area. What is the Package Cache The package cache is an area…