Internal Subscription issue between openHistorian and openPDC

Hi I am trying to create the internal subscription in openHistorian receiving data from openPDC. after following the instruction

the CPU usage ramps up to 100% and no device is found. After checking the console, I have found following warning.

The connection string is

interface=; compression=true; autoConnect=true; securityMode=None; server=; internal=True; receiveInternalMetadata=True; receiveExternalMetadata=True; outputMeasurements={FILTER ActiveMeasurements WHERE Protocol = ‘GatewayTransport’}

Could anyone help? Much appreciated.


1 Like

The issue is the server in your connection string: server= The openHistorian itself listens to port 6175, so you’ve created a tight feedback loop between the openHistorian’s data subscriber and its data publisher. openHistorian is consuming its own data in the data subscriber and feeding it back into the data publisher via the measurement routing engine. Naturally, this will cause CPU to ramp up because it’s constantly processing the same data points over and over again in a never-ending loop, and if you let the system run for a long enough time it will use up all the memory too as it creates new measurements and feeds them into the loop.

If openPDC is running on the same computer as openHistorian, then you should be able to simply change the port number from 6175 to 6165. If the openPDC is on another computer, you should also modify the IP address to point to port 6165 on the appropriate machine.

Hi Stephen

Thanks for your insightful reply. It is indeed a feedback as what you said. After changing the port, the issue is solved. Thanks again!