rdisp/TRACE_LOGGING is a SAP Parameter attribute which is used to control Switch on/off trace logging information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
The parameter can be used if the trace is to be active for a longer
period for troubleshooting purposes. In order that the trace files do
not reach an unlimited size, it is possible to activate an automatic
resent in case the files exceed a predefined size. Every trace file is
saved to a "log" file before the reset. This log file has extended the
name of the trace file with the suffix ".old". The
See SAP Parameter Documentation for full SAP documentation for this profile parameter.