Long running sessions limit the efficient of revision gc as they keep reference to old node states.
We should consider to add an MBean through which all sessions can be enforced to refresh. This would provide clients with means to fine tune revision gc by first calling that MBean and then triggering a gc cycle. IMO this is preferable to directly enforcing a refresh from the garbage collector. The latter is too invasive and also not required when there are no long running sessions. Offering this functionality to clients as an additional knob to turn is safer.