Starting in Strategy 9.3.1, additional logging is available for Distribution Services. The "Scheduler Trace" log is useful when troubleshooting the full activity of the Scheduler process in Distribution Services. The Scheduler process is responsible for constantly checking for newly created subscriptions and notifying the Intelligence Server about when they should be executed.
The trace can be found in the Strategy Diagnostics and Performance Logging tool as shown below:

Note: This trace is not enabled by default. An existing or new "File Log" destination must be selected for this logging to be used.
This log will show every time the Scheduler checks for newly created subscriptions in order to notify the Intelligence Server that any newly created subscription will need to be executed in the future. Additionally, it will log any Event and Time triggered subscription execution request made to the Intelligence Server.
2013-12-20 20:40:00.013-05:00 Enter MSIScheduler::OnTriggerSchedule(); iScheduleObjectID = 2D4930B811D49BB1C0000786C901614F2013-12-20 20:40:00.138-05:00 Return from MSIScheduler::OnTriggerSchedule(); iScheduleObjectID = 2D4930B811D49BB1C0000786C901614F2013-12-20 20:43:59.024-05:00 Enter MSIScheduler::SubmitNCSRequestsForTrigger()2013-12-20 20:43:59.027-05:00 Return S_OK from MSIScheduler::SubmitNCSRequestsForTrigger().2013-12-20 20:43:59.369-05:00 Enter MSIScheduler::SubmitNCSRequestsForTrigger()2013-12-20 20:43:59.372-05:00 Return S_OK from MSIScheduler::SubmitNCSRequestsForTrigger().2013-12-20 20:43:59.640-05:00 Return S_OK from MSIScheduler::ProcessEvent()2013-12-20 20:44:40.922-05:00 Return S_OK from MSIScheduler::ProcessEvent()2013-12-20 20:49:59.994-05:00 Enter MSIScheduler::OnTriggerSchedule(); iScheduleObjectID = 2D4930B811D49BB1C0000786C901614F2013-12-20 20:50:02.291-05:00 Return from MSIScheduler::OnTriggerSchedule(); iScheduleObjectID = 2D4930B811D49BB1C0000786C901614F2013-12-20 21:00:00.026-05:00 Enter MSIScheduler::OnTriggerSchedule(); iScheduleObjectID = 2D4930B811D49BB1C0000786C901614F2013-12-20 21:00:00.530-05:00 Return from MSIScheduler::OnTriggerSchedule(); iScheduleObjectID = 2D4930B811D49BB1C0000786C901614F2013-12-20 21:10:00.026-05:00 Enter MSIScheduler::OnTriggerSchedule(); iScheduleObjectID = 2D4930B811D49BB1C0000786C901614F2013-12-20 21:10:00.231-05:00 Return from MSIScheduler::OnTriggerSchedule(); iScheduleObjectID = 2D4930B811D49BB1C0000786C901614F2013-12-20 21:20:00.026-05:00 Enter MSIScheduler::OnTriggerSchedule(); iScheduleObjectID = 2D4930B811D49BB1C0000786C901614F2013-12-20 21:20:00.320-05:00 Return from MSIScheduler::OnTriggerSchedule(); iScheduleObjectID = 2D4930B811D49BB1C0000786C901614F2013-12-20 21:21:12.003-05:00 Enter MSIScheduler::OnTriggerSchedule(); iScheduleObjectID = 682CEA6A4BC38BAE3ECD7BAA1B5C8D1F2013-12-20 21:21:12.005-05:00 Enter MSIScheduler::SubmitNCSRequestsForTrigger()2013-12-20 21:21:12.008-05:00 Return S_OK from MSIScheduler::SubmitNCSRequestsForTrigger().2013-12-20 21:21:12.179-05:00 Return from MSIScheduler::OnTriggerSchedule(); iScheduleObjectID = 682CEA6A4BC38BAE3ECD7BAA1B5C8D1F2013-12-20 21:29:59.889-05:00 Enter MSIScheduler::OnTriggerSchedule(); iScheduleObjectID = 2D4930B811D49BB1C0000786C901614F