From Apache OpenOffice Wiki
The Log purpose environment allows to log every UNO call to a defined component. The runtime environment variable UNO_ENV_LOG defines which components should be logged. The value is a list of component names separated by semicolon (;). The log file must have been defined by the RTL_LOGFILE variable.
Specifying the to be logged components via environment variables.
setenv "UNO_ENV_LOG" "com.sun.star.sdbcx.comp.hsqldb.Driver"
setenv "RTL_LOGFILE" "/tmp/log_test"
The would trace all calls from the HsqlDB driver in OOo.
Runtime environment variable: