Constant increase in memory usage of the zenon OPC UA server in the process gateway under specific circumstances until the process can no longer allocate more memory and closes with an error message
Summary
Under specific circumstances where an OPC UA client sends constant read requests without a prior RegisterNodes request, the zenon OPC UA server in the process gateway continuously uses more and more memory until after some time, days, depending on the read requests, the process can no longer allocate any more memory and fails with an error message.
Regular OPC UA clients that communicate through subscriptions do not cause this behaviour.
OPC UA Clients that send frequent read requests and call RegisterNodes, also do not cause this behaviour.
It is recommended that clients that peform read requests, call RegisterNodes once prior to sending read requests.
Description
Under specific circumstances where an OPC UA client sends constant read requests without a prior RegisterNodes request, the zenon OPC UA server in the process gateway continuously uses more and more memory until after some time, days, depending on the read requests, the process can no longer allocate any more memory and fails with an error message.
Regular OPC UA clients that communicate through subscriptions do not cause this behaviour.
OPC UA Clients that send frequent read requests and call RegisterNodes, also do not cause this behaviour.
It is recommended that clients that peform read requests, call RegisterNodes once prior to sending read requests.
Solution
An issue has been addressed in the OPC UA server in the process gateway where memory allocated to process the values of a read request was not correctly released and would eventually cause the OPC UA server in the process gateway to run out of memory. Now the memory is correctly released.
Issue Number: 36092
Fixed on Date: 16.3.2016
Versions: 7.20 0 BUILD 26944