Like a few utilities, we are still stuck at 9.3.1 for a few more months before upgrading to 10.2.x, but I think that these ideas apply at 10.2.x as well. As usage of our system has increased this year so that someone is editing in our production geodatabase almost 24/7, we've had more problems with the compress operation getting locked by long running batch processes or ArcMap reconciles. The compress sits in an idle wait state waiting for a PL/SQL table lock on a particular D-table to become available. If we're unlucky, it waits for the PL/SQL table lock while holding a state lock on the SDE.DEFAULT version, which causes a system outage. It would be nice if the compress operation allowed setting a maximum wait time, after which the compress would kill itself. It would be even nicer if compress weren't required to use PL/SQL table locks on D-tables while editors are in the system.