The OPC UA process gateway closes with an unhandled exception or stops responding after communicating for several days with an OPC UA client via subscribtions.

The OPC UA process gateway closes with an unhandled exception or stops responding after communicating for several days with an OPC UA client via subscribtions.

Summary

With an OPC UA process gateway running and an OPC UA client connected that retrieves variable values through subscribtions, the OPC UA process gateway in 7.10 may close unexpectedly with an unhandled exception after communicating for several days.

In the same configuration, the OPC UA process gateway and the runtime in 7.0 may stop responding with a high CPU load, after communicating for several days. As a result of the high CPU load of the OPC UA server in 7.0, the memory usage of the zenon runtime process increases and will eventually lead to an out of memory situation.

Description

With an OPC UA process gateway running and an OPC UA client connected that retrieves variable values through subscribtions, the OPC UA process gateway in 7.10 may close unexpectedly with an unhandled exception after communicating for several days.

In the same configuration, the OPC UA process gateway and the runtime in 7.0 may stop responding with a high CPU load, after communicating for several days. As a result of the high CPU load of the OPC UA server in 7.0, the memory usage of the zenon runtime process increases and will eventually lead to an out of memory situation.

Solution

An issue was addressed in the OPC UA process gateway where publish requests for subscribtions were not removed from a map after the server sent the publish response to the OPC UA client. Eventually the OPC UA process gateway could no longer store any further publish requests and went into an unstable state.

The OPC UA process gateway now retains the Publish Requests from an OPC UA client, so that the client could cancel the request if necessary, and removes the publish request after the publish response is sent to the client.



Issue Number: 30230
Fixed on Date: 21.8.2013
Versions: 7.00 0 BUILD 11 | 7.10 0 BUILD 7192