It cycles through all the timed jobs and recalculates the next run time like this below:
8/2/2010 6:47:40 AM Debug Next execution (6) for job 'xxx' is: 8/2/2010 8:00:00 AM
8/2/2010 6:47:40 AM Debug Next execution (6) for job 'yyy' is: 9/1/2010 7:15:00 AM
When this happens the server becomes unresponsive and some jobs do not start. It appeared the CPU usage was maxed out at 100% so we couldn't determine what exactly was going on with the server when this was happening. We eventually had to reboot the virtual machine that had VisualCron installed on it. Throughout the day yesterday we had several instances where the timed jobs would recalculate their start times. Here is a list of the times it occurred yesterday.
8/2/2010 6:47:40 AM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 7:26:09 AM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 8:44:52 AM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 9:49:52 AM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 9:51:05 AM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 9:52:08 AM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 9:53:37 AM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 9:54:27 AM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 10:03:18 AM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 10:04:33 AM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 10:05:07 AM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 10:05:25 AM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 10:06:03 AM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 11:18:59 AM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 2:27:11 PM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 3:01:40 PM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 3:02:00 PM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 3:21:35 PM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 3:27:36 PM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 3:28:15 PM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 3:28:42 PM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 3:31:20 PM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 3:31:44 PM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 4:07:59 PM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 4:08:18 PM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 4:08:52 PM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 4:10:21 PM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 4:13:37 PM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 4:22:00 PM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 4:22:01 PM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 4:23:17 PM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 4:23:18 PM Debug Triggers will be recalculated due to time change in the system.
8/2/2010 4:23:40 PM Debug Triggers will be recalculated due to time change in the system.
It is strange because we did not experience this behavior when we had both virtual machines running at the same time but on separate physical hardware. It occurred once we moved both VM's to the same server that we had these issues. Once we shut down the second instance of VisualCron the first one immediately became responsive and no longer threw messages indicating that "triggers will be recalculated due to time change in the system". At this point we have made the determination to dedicate one physical server for VisualCron and abandon the idea of using virtual machines with the software. Right now we have our second virtual machine with VisualCron shut down so we are not currently experiencing any issues.
Is there anyone that has more than 1 VisualCron server running in a virtual environment on the same hardware?
Support, let me know if you would like more information.
Thanks,
Peter