The standard output format of an MDC log across components consists of 3 colon-separated values in the following order: webapp:transport:requestId. The requestId value is left-padded hex, so an example output could be the following: ROOT:w:0000000a.

For the transport, the following abbreviations are used to determine the source:

For any request, the Tomcat Access log outputs this format exactly as stated if the pattern was modified. However, any message or standard output within the ABL Agent log is preceded by R- when the feature is enabled. If the message only comes from the internal Multi-Session Agent code then the output appears as R-?:?:? or simply R-mtapsv:-:?. When a message is output during execution of code from a transport request, then OERequestInfo is available and the expected values are provided for webapp, transport, and request ID.