A new build with the fix for the deadlock issue is now available, numbered 5.35.1173.1 (or higher). It is available from your reseller, and will be posted on this website shortly too.

Best regards

I was able to reproduce the problem (using the EasyOpcUADemo application from the current QuickOPC 5.35 build, and the 'uaserverc' OPC server v1.6.0-341). I can confirm it is a client-side deadlock.

I will work on a fix and make a post here when there is an update.

I was using opc.tcp.
I've also contacted the support via email, and given the dump and some test applications to them as well.

It's true that dump files won't solve everything, but they usually do point in the general area of where the issue is, which helps to create a reproducible situation.

Hello,

no, this is not a known problem. We will try to reproduce it here - I will let you know the outcome then.

Which protocol do you use (opc.tcp: or htpp: )?

You have mentioned a file attachment, but there is nothing attached to the forums post. If it was due to the fact that the .7z file extension was not allowed, please retry - I will enable it in several minutes. Note that I am not sure whether the memory dump would be helpful for analysis - it is fairly complicated to work with it, and we typically need an ability to repro the problem and analyze it live in debugger.

Best regards

Hi,

Whilst integrating OPC UA in Delphi XE3 (using the QuickOPC v5.35) I found that there's a possible deadlock.
For it to happen, I must first subscribe to one or multiple nodes. Then I restart the OPC server and whilst the OPC SDK is busy re-connecting, I try to write a value to the subscribed node. If the timing is right, a deadlock occurs.

Thinking that it was something in my program, I tested the EasyOpcUADemo.exe example (in the DemoNet folder), and it suffers from the same thing: trying to write a value to a subscribed node, at the "right" moment after a server restart, causes it to deadlock too.

This deadlock does not happen every time, so it can be a bit tricky to find the right moment where it happens. I have attached a full memory dump (with 7zip) of your demo application when it has hung.

I've been using a demo server from Unified Automation (uaserverc.exe, v1.5.1.313). To reproduce using your demo program: I start the uaserver.exe, then start your demo application, connect it to the server and subscribe to one value (e.g. Demo.Scalar.Byte). I then press 'r' in the OPC server console to make it restart, wait 3 seconds before it does so and then try to write a value. Repeat this until the deadlock occurs.

Is this a know issue? Can this be fixed?

Thanks!