In the past, we have examined in-depth the DB2 performance problems that might be found in a typical DB2 installation. My purpose in doing this was to show you how a methodical review can help you discover ways to reduce system costs. Good application review and positive changes can even save substantial investment in new hardware.
Be sure to check through the various blogs to hone in on the type of analysis essential for your site. Below is a review of some of the topics we've covered over the past four months.
Analyze Your System
- Use RUNSTATS to determine what is really going on in your system. Redo and review them for analysis as the system is implemented and grows.
- Using performance reports and drilling down into the DB2 catalog can give you valuable information about specific performance problems. Use these tools to discover:
- Processes that use excessive resources
- Underlying data objects that might be causing some performance problems.
- Reasons why data object definition, particularly index definition, might be causing performance problems.
- Determine the number of abends, deadlocks and dumps. These can take a tremendous amount of CPU resources and should be researched and eliminated as soon as possible.
- Check secondary extents for all data sets, including SortWorks
- Check to see if there are lots of times that a write engine is not available. Look at the size of your buffer pools, look at the deferred write threshold and look at the timing of your jobs and possibly eliminate the times write engines are not available.
- Verify the checkpoint frequency of your systems. Having the correct checkpoint frequency can provide the proper checkpoints for disaster and regular recoveries of your databases and system. The recommended checkpoint frequency is about every 10 to 15 minutes. So depending on how busy your system is adjust the number of log records accordingly.
- Make sure that your Work Load Manger (WLM) is set up properly to distribute the CPU resources adequately and properly to the various database systems and applications. Having the database at the same or below the applications can cause huge performance and overall throughput problems.
- Insure that your DB2 System Maintenance is at the appropriate level. Do you have maintenance plans that include checking the Service Pack levels?
To be continued...
_______________________________________________________Dave Beulke is an internationally recognized DB2 consultant, DB2 training and DB2 education instructor.Dave helps his clients improve their strategic direction, dramatically improve DB2 performance and reduce their CPU demand, saving millions in their systems, databases and application areas within their mainframe, UNIX and Windows environments. Search for more of Dave Beulke’s DB2 Performance blogs on DeveloperWorks and at www.davebeulke.com.