Performance Monitoring Infrastructure (PMI) | Trace and logging


PMI predefined statistic sets


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In IBM WebSphere Application Server V6, PMI provides four predefined statistic sets that can be used to enable a set of statistics. These four predefined statistic sets are:

You can also use the Custom setting to define your own statistic set.

Statistic set Description
None All statistics are disabled.
Basic Statistics specified in J2EE 1.4, as well as top statistics like CPU usage and live HTTP sessions, are enabled. This set is enabled by default and provides basic performance data about runtime and application components.
Extended Basic set plus key statistics from various WAS components like WLM and Dynamic caching are enabled. This set provides detailed performance data about various runtime and application components.
All All statistics are enabled.
Custom Enable or disable statistics individually.


Predefined statistic sets

If Extended or All statistic set is selected, PMI can have a very large memory footprint on the JVM heap. WebSphere Commerce is very dependent on caching inside the JVM to achieve optimal performance. Leaving PMI statistics collection at a high level can severely impact stability and performance.

Most of what PMI can provide is either not necessary for WebSphere Commerce or can be obtained from logs. For example, runtime JVM statistics can be obtained from a verbose GC log. Dynamic caching statistics can be viewed from a cache monitor.

Currently, IBM recommends that you use PMI only for monitoring...

For details on how PMI works, see WAS V6 Scalability and Performance Handbook, SG24-6392.