Performance Monitoring Infrastructure (PMI) Request Metrics is a tool that allows you to track individual transactions. As a transaction flows through the system, Request Metrics tacks on additional information so that the log records from each component can be correlated, building up a complete picture of that transaction. The information tracked may be saved to log files for later retrieval and analysis. Request metrics are only available through the HTTP Plug-in for WebSphere Application Server for z/OS.
The trace records for PMI Request Metrics data are output to the Web server plug-in log file, if it is enabled. The default directory for this log file is <$WAS_ROOT/logs> (or the name given to your server <$WAS-ROOT/logs/server_name>) and default name is http_plugin.log. You can, however, specify a different name and location for the log file.
In the WebSphere Application Server log file the trace record format is:
PMRM0003I: parent:ver=n,ip=n.n.n.n,time=nnnnnnnnnn,pid=nnnn,reqid=nnnnnn,event=nnnn - current:ver=n,ip=n.n.n.n,time=nnnnnnnnnn,pid=nnnn,reqid=nnnnnn,event=nnnn type=TTT detail=some_detail_information elapsed=nnnn
In the Web server plug-in log file the trace record
format is:
PLUGIN: parent:ver=n,ip=n.n.n.n,time=nnnnnnnnnn,pid=nnnn,reqid=nnnnnn,event=nnnn - current:ver=n,ip=n.n.n.n,time=nnnnnnnnnn,pid=nnnn,reqid=nnnnnn,event=nnnn type=TTT detail=some_detail_information elapsed=nnnn bytesIn=nnnn bytesOut=nnnn
The trace record format is composed of two correlators: a parent correlator and current correlator. The parent correlator represents the upstream request and the current correlator represents the current operation. If the parent and current correlators are the same, then the record represents an operation that occurred as it entered WebSphere Application Server.
For transactions that originated at the application server port (the parent and current correlators are the same), the HTTP server plug-in will not see the transaction. Therefore, the request metric data will not be written to the trace log file for the Web server plug-in.
To correlate trace records for a particular request, collect records with a message ID of PMRM0003I from the appropriate application server log files and the PLUGIN trace record from the Web server plug-in log file. Records are correlated by matching current correlators to parent correlators. The logical tree can be created by connecting the current correlators of parent trace records to the parent correlators of child records. This tree shows the progression of the request across the server cluster.
The parent correlator is denoted by the comma separating fields following the keyword "parent:". Likewise, the current correlator is denoted by the comma separating fields following "current:".
The fields of both parent and current correlators are as follows:
Following the parent and current correlators, is the metrics data for timed operation:
The type and detail fields are described as follows: