Under specific timing circumstances the OPC UA server in the process gateway does not correctly remove an online container in the runtime which may lead to a continued increase in resource consumption and finally resource exhaustion.

Under specific timing circumstances the OPC UA server in the process gateway does not correctly remove an online container in the runtime which may lead to a continued increase in resource consumption and finally resource exhaustion.

Summary

The OPC UA server in the process gateway communicating with an OPC UA client that performs irregular and unexpected frequent requests may under specific timing conditions not succeed to successfully remove an online container in the runtime for a subscription created by the OPC UA client.   The specific OPC UA client creates a subscription and adds monitored items, and immediately after deletes either the subscription again or deleted the monitored items again. Under specific circumstances and timing conditions, the removal of the online container was not performed by the OPC UA server.   With an OPC UA client performing like this over a prolonged period of time, the number of orphaned online container in the runtime increases until eventually the system becomes irresponsive.

Description

The OPC UA server in the process gateway communicating with an OPC UA client that performs irregular and unexpected frequent requests may under specific timing conditions not succeed to successfully remove an online container in the runtime for a subscription created by the OPC UA client.   The specific OPC UA client creates a subscription and adds monitored items, and immediately after deletes either the subscription again or deleted the monitored items again. Under specific circumstances and timing conditions, the removal of the online container was not performed by the OPC UA server.   With an OPC UA client performing like this over a prolonged period of time, the number of orphaned online container in the runtime increases until eventually the system becomes irresponsive.

Solution

 An issue has been addressed in the OPC UA server where under specific timing conditions deletion of a subscription or monitored items, immediately after a subscription is created or monitored items were added, could lead to a situation where the online container was not removed. Now the response to the OPC UA server regarding the success of the creation of the subscription or adding of the monitored items, or the deletion of the subscription or the deletion of the monitored items, is delayed until the action has been fully completed.  

Issue Number: 37564
Fixed on Date: 16.12.2016
Versions: 7.50 0 BUILD 33934