Deleting and Adding the same device


This is related to OpenHistorian 2.6. I have 4 servers all subscribing to each other in a daisy chain fashion and added a device to the publishing server. I then used Grafana on the final subscribing server and then recorded history for a few days.

Then I went and deleted the device from the main publishing server. Sure enough, shortly after, the history disappears from Grafana on the subscribing server.

I then added back the device with the exact same details, and the history started up again on Grafana, but only the newer history, not when the device was originally added.

My question is, I’m guessing the original history is not physically deleted and that new GUID’s are generated when you add the same device it will in fact have different identifiers. Is there some way of associating the newly added device to the older added device short of making a backup of the database or writing some database scripts?

Correct. When a new device is added, measurements associated with the new device get new Guid’s.

Generally we don’t delete and readd to avoid this very issue. Instead, if we want a configuration change we use the “update configuration” process.

In the openHistorian UI (not web) - if you go to browse devices, you will notice a gear with a pencil icon to the right of the device.

Clicking this will run through the a process which is similar to adding a device, but instead attempts to preserve as many of the original Guids as possible - new measurements will get new Guids, etc.