Typically, there are multiple processes across several nodes in a distributed system. When a request comes to a process, the process may send the request to one or more downstream processes.
Trace records may be generated for each process with associated elapsed times for that process. These trace records may be correlated together to build a complete picture of the request flow through the distributed system, similar to the diagram in Measuring data requests (Performance Monitoring Infrastructure Request Metrics).
The process response time monitored by Request Metrics can be viewed through the Application Response Measurement (ARM) interface and system logs. For requests that originate from either an HTTP request or the remote interface of an enterprise bean, Request Metrics captures response times for the initiating request and any related downstream invocations. If the request originated as an HTTP request, response times are generated for web server plug-in (only available when using web server port), the web container, the EJB container, and JDBC calls. If the request originated as a remote EJB call, response times are generated for the EJB container and JDBC calls. Note that the JDBC response time are only traced for the WebSphere 5.0 data source. No response time will be traced for WebSphere 4.0 data source.
When active, Request Metrics compares each incoming request to a set of known filters. Three types of filters are supported:
Trace records are generated and logged for the Web Server plug-in, servlets (WebContainer), remote enterprise bean calls, and Java Database Connectivity (JDBC drivers).