Workflow foundation - balanced scenario

Question

I have a balanced environment where there are 2 workflow application instances running. This are called from a sharepoint farm which is also balanced with 2 front ends.

The workflow make use of persistance and both workflows are connected to the same persistence database.

We are receiving the following error and we think it could be related to the balanced environment. This is because we have tested the workflows thouroughly on a non-balanced environment and we never received this error.

System.ServiceModel.FaultException: Operation 'DoSumbit|{http://tempuri.org/}IMyContract' on service instance with identifier '92d66ac3-da5a-48fb-a88d-a82820471fb0' cannot be performed at this time. Please ensure that the operations are performed in the correct order and that the binding in use provides ordered delivery guarantees. Server stack trace: at System.ServiceModel.Channels.ServiceChannel.HandleReply(ProxyOperationRuntime operation, ProxyRpc& rpc) at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs, TimeSpan timeout) at System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage methodCall, ProxyOperationRuntime operation) at System.ServiceMo... 211969e8-8427-4c55-9cd5-6ed911cd22d7 11/29/2011 09:32:28.01* w3wp.exe (0x0DCC) 0x082C SharePoint Foundation Runtime tkau Unexpected ...del.Channels.ServiceChannelProxy.Invoke(IMessage message) Exception rethrown at [0]: at ....

Any assistance would be greatly appreciated.

Regards,

Joseph

Answer 1

Normally you get this error for the reason in the message. The workflow instance is not in a state where it can process the requested message. Normally this means the workflow is busy, or more likely the workflow is just waiting for some other event and the Receive activity that is supposed to handle this event isn't active.

You can also into problems when one host receives a message for a workflow instance loaded by another host but in that case you normally get an exception indicating that the workflow instance is locked by another WSH and can't be loaded at the time.