SDEINTERCEPT and SDEINTERCEPTLOC
Awhile ago, I had a ArcSDE problem that required ESRI technical support to help trouble-shoot. The problem was odd but was resolved by rebooting the server.
During the process, though, the support person had me set a couple of environment variables for logging SDE activity on the client machine.
The settings were SDEINTERCEPT and SDEINTERCEPTLOC.
From ESRI’s Help, SDEINTERCEPT specifies what activity to log and SDEINTERCEPTLOC specifies where to save the log files.