Example
In this example, both machines are used as clients.
To illustrate the use of client IP filtering, one client IP filter (192.168.0.2) is defined and enabled. This action allows tracing of requests originating from the enterprise bean machine through http://192.168.0.1/hitcount?selection=EJB. However, requests originating from the servlet machine are not traced since the client IP address is not in the filter list.
By only creating a client IP filter, any request from that client IP address is effectively traced. This tool can be effective for locating performance problems with systems under load. If the normal load is originating from other IP addresses, then their requests are not traced. By using the defined client IP address to generate requests, you can see performance bottlenecks at the various hops by comparing the trace records of the loaded system to trace records from a non-loaded run. This ability can help focus tuning efforts to the correct node and process within a complex deployment environment.
Make sure Request Metrics is enabled using the administrative console. Also, make sure the trace level is set to at least hops (writing request traces at process boundaries). Using the configuration listed above, send a request through the HitCount servlet from the enterprise bean machine http://192.168.0.1/hitcount?selection=EJB.
In this example, at least three trace records are generated:
The two trace records appearing on 192.168.0.1 are similar to the following:
PLUGIN: parent:ver=1,ip=192.168.0.1,time=1016556185102,pid=796,reqid=40,event=0 - current:ver=1,ip=192.168.0.1,time=1016556185102,pid=796,reqid=40,event=1 type=HTTP detail=/hitcount elapsed=60 bytesIn=0 bytesOut=2252
PMRM0003I: parent:ver=1,ip=192.168.0.1,time=1016556185102,pid=796,reqid=40,event=0 - current:ver=1,ip=192.168.0.1,time=1016556186102,pid=884,reqid=40,event=1 type=URI detail=/hitcount elapsed=60
The trace record appearing on 192.168.0.2 is similar to the following:
PMRM0003I: parent:ver=1,ip=192.168.0.1,time=1016556186102,pid=884,reqid=40,event=1 - current:ver=1,ip=192.168.0.2,time=1016556122505,pid=9321,reqid=40,event=1 type=EJB detail=com.ibm.defaultapplication.ConcreteIncrement_501bb55e.increment elapsed=40
Note: The detail for an EJB call is close to the class name of the EJB but not exactly the class name.