This obviously only works when you are trouble shooting a specific issue, not when you need to investigate something that happened in the past (where the logging for the session wasn't enabled). However, it has proven to be an excellent tool for troubleshooting issues in the system.
I have used session-based logging both when I worked at Ericsson (the AXE system), and at Symsoft (the Nobill system), and both were excellent. However, I get a feeling that they are not in widespread use (may be wrong on that though), so that's why I wrote a description of them: http://henrikwarne.com/2014/01/21/session-based-logging/
And it invites timing-based heisenbugs (enable tracing, problem goes away).
Still a neat approach, however.