In addition to the user-configurable logging functionality described in Logging and debugging, IBM TDI is instrumented throughout its code with tracing statements, using the JLOG framework. This is a logging library similar to Log4J, but which is used inside TDI specifically for tracing and First Failure Data Capture (FFDC). To which extent this becomes visible to you, the end user, depends on a number of configuration options in the global configuration file jlog.properties, and the Server command line option -T.
Normally, we should be able to troubleshoot, debug and support the solution using the logging options described in the chapter, Logging and debugging. However, when you contact IBM Support for whatever reason, they may ask you to change some parameters related to the tracing functionality described here to aid the support process.