As a developer using DB2 for the first time, I'm not familiar with what the best database performance analysis tools are for it.
I'm wondering what others have found useful in terms of tools that come with DB2, and any third-party tools available for it.
e.g. Anything better than others for things like query planning, CPU measurement, index usage, etc.?
You don't specify which version/release of DB2 you're running, or whether you're running the mainframe (z/OS) version or DB2 for Linux, UNIX, and Windows (also known as DB2 for LUW).
If you're running DB2 on z/OS, talk to your DBA and you'll find out exactly which monitoring and analysis tools have been licensed.
If it's DB2 for LUW you're using, there are various structures and routines you can access directly in DB2 to capture detailed performance information. IBM adds more of these features with each new DB2 release (e.g. version 9.5 vs. 9.7), so be sure to access the version of the documentation for your specific release. Here is the monitoring guide for 9.5 and here is the 9.7 monitoring guide.
The challenge will be to capture and analyze that performance data in some useful way. BMC, CA, DBI, IBM, and even HP have very good third-party tools to help you do that. Some of them are even free.
On the open-source side, monitors from GroundWork Open Source and Hyperic HQ Open Source have some DB2 support, but you'll need to spend some time configuring either of those environments to access your DB2 server.
Many of the tools mentioned above track some combination of DB2 health and performance indicators, and may even alert you when something about DB2 or its underlying server has entered a problem status. You will face choices over what to use as the criteria for triggering alerts, versus the KPIs you simply want to capture without ever alerting.
There are a lot of monitoring tools out there that can be taught how to watch DB2, but one of the most versatile and widely used is RRDtool, either on its own with a collection of custom DB2 scripts, or as part of a Cacti or Munin installation, which automates many (but not all) aspects of working with RRDtool. The goal of RRDtool is to capture any kind of numeric time-series data so it can be rendered into various graphs; it has no built-in alert capabilities. Implementing RRDTool involves choosing and describing the data points you intend to capture and allocating RRDtool data files to store them. I use it a lot to identify baseline performance and resource utilization trends for a database or an application. The PNG bitmaps it produces can be integrated into a wide variety of IT dashboards, provided those dashboards are customizable.