I'm trying to query my local queues on my machine, with the follow code:
var c = new MessageQueueCriteria();
c.MachineName = Environment.MachineName;
var queues = MessageQueue.GetMessageQueueEnumerator(c);
but the code throws an exception on the second line complaining:
A workgroup installation computer does not support the operation.
Stack trace: at System.Messaging.MessageQueue.GetMachineId(String machineName)
at System.Messaging.MessageQueueCriteria.set_MachineName(String value)
and the MessageQueueErrorCode enum is set to System.Messaging.MessageQueueErrorCode.UnsupportedOperation.
The strange thing is I am on a domain and not a workgroup! and other application (QueueExplorer) seem to work file. Any ideas how I can get around it?
Update: Seems the error comes from running this piece of code that is in the setter of the property, not sure how to fix it though.
new MessageQueuePermission(MessageQueuePermissionAccess.Browse, "*").Demand();
The class MessageQueueCriteria is used to filter PUBLIC message queues when using the GetPublicQueues method. To be able to browse for public queues you must enable the MSMQ Active Directory Services Integration feature. If your computer is joined to a domain is not enough.
If you would like to browse your local PRIVATE queues you should use:
MessageQueue[] queues = MessageQueue.GetPrivateQueuesByMachine(Environment.MachineName);
Related
I'm using the MPI.NET library, and I've recently moved my application to a bigger cluster (more COMPUTE-NODES). I've started seeing various collective functions hang indefinitely, but only sometimes. About half the time a job will complete, the rest of the time it'll hang. I've seen it happen with Scatter, Broadcast, and Barrier.
I've put a MPI.Communicator.world.Barrier() call (MPI.NET) at the start of the application, and created trace logs (using the MPIEXEC.exe /trace switch).
C# code snippet:
static void Main(string[] args)
{
var hostName = System.Environment.MachineName;
Logger.Trace($"Program.Main entered on {hostName}");
string[] mpiArgs = null;
MPI.Environment myEnvironment = null;
try
{
Logger.Trace($"Trying to instantiated on MPI.Environment on {hostName}. Is currently initialized? {MPI.Environment.Initialized}");
myEnvironment = new MPI.Environment(ref mpiArgs);
Logger.Trace($"Is currently initialized?{MPI.Environment.Initialized}. {hostName} is waiting at Barrier... ");
Communicator.world.Barrier(); // CODE HANGS HERE!
Logger.Trace($"{hostName} is past Barrier");
}
catch (Exception envEx)
{
Logger.Error(envEx, "Could not instantiate MPI.Environment object");
}
// rest of implementation here...
}
I can see the msmpi.dll's MPI_Barrier function being called in the log, and I can see messages being sent and received thereafter for a passing and a failing example. For the passing example, messages are sent/received and then the MPI_Barrier function Leave is logged.
For the failing example it look like one (or more) of the send messages is lost - it is never received by the target. Am I correct in thinking that messages lost within the MPI_Barrier call will mean that the processes never synchronize, therefore all get stuck at the Communicator.world.Barrier() call?
What could be causing this to happen intermittently? Could poor network performance between the COMPUTE-NODES be a cause?
I'm running MS HPC Pack 2008 R2, so the version of MS-MPI is pretty old, v2.0.
EDIT - Additional information
If I keep a task running within the same node, then this issue does not happen. For example, if I run a task using 8 cores on one node then fine, but if i use 9 cores on two nodes I'll see this issue ~50% of the time.
Also, we have two clusters in use and this only happens on one of them. They are both virtualized environments, but appear to be set up identically.
In Tibco, sometimes warnings are printed to the console, e.g.:
2014-06-25 18:13:22 RV: TIB/Rendezvous Error Not Handled by Process:
{ADV_CLASS="WARN" ADV_SOURCE="RVCM"
ADV_NAME="REGISTRATION.NOT_CERTIFIED.cm.test.subject"
subject="cm.test.subject" sender="cm.sender.cmname"}
I am using the .NET wrappers for Tibco. It appears as if these errors are not actually making it into the .NET, and they can't be caught with try/catch so they can be handled appropriately.
Is there any way to handle this error in .NET? Perhaps some method of registering a handler to handle errors such as this? Or alternatively, is there a method to redirect these warnings into a sink other than the console, e.g. a log file?
The solution is to add a "catch all" handler.
The current subject that I was listening to was:
private readonly string _subjectDeliveryConfirm = "_RV.INFO.RVCM.DELIVERY.CONFIRM.>";
To add a catch all, add another listener on:
private readonly string _subjectDeliveryGlobal = ">";
When you add a new listener, remember to use a separate Listener concrete class per listener, or else Tibco will mysteriously stop working after the first message (see the demo code for how to create multiple listeners).
_confirmListener1 = new Listener(Queue.Default, _netTransport, _subjectDeliveryConfirm, null);
_confirmListener1.MessageReceived += new MessageReceivedEventHandler(OnCertifiedMessageConfirmed);
// Subscribe to error messages, in particular error messages related to remote listener processes
// disappearing.
_confirmListener2 = new Listener(Queue.Default, _netTransport, _subjectDeliveryGlobal, null);
_confirmListener2.MessageReceived += new MessageReceivedEventHandler(OnTibcoCatchAll);
There is lots of sample C# code in the \src\ directory for the Tibco install that illustrates the techniques shown above.
I have a windows service, running workflows. The workflows are XAMLs loaded from database (users can define their own workflows using a rehosted designer). It is configured with one instance of the SQLWorkflowInstanceStore, to persist workflows when becoming idle. (It's basically derived from the example code in \ControllingWorkflowApplications from Microsoft's WCF/WF samples).
But sometimes I get an error like below:
System.Runtime.DurableInstancing.InstanceOwnerException: The execution of an InstancePersistenceCommand was interrupted because the instance owner registration for owner ID 'a426269a-be53-44e1-8580-4d0c396842e8' has become invalid. This error indicates that the in-memory copy of all instances locked by this owner have become stale and should be discarded, along with the InstanceHandles. Typically, this error is best handled by restarting the host.
I've been trying to find the cause, but it is hard to reproduce in development, on production servers however, I get it once in a while. One hint I found : when I look at the LockOwnersTable, I find the LockOnwersTable lockexpiration is set to 01/01/2000 0:0:0 and it's not getting updated anymore, while under normal circumstances the should be updated every x seconds according to the Host Lock Renewal period...
So , why whould SQLWorkflowInstanceStore stop renewing this LockExpiration and how can I detect the cause of it?
This happens because there are procedures running in the background and trying to extend the lock of the instance store every 30 seconds, and it seems that once the connection fail connecting to the SQL service it will mark this instance store as invalid.
you can see the same behaviour if you delete the instance store record from [LockOwnersTable] table.
The proposed solution is when this exception fires, you need to free the old instance store and initialize a new one
public class WorkflowInstanceStore : IWorkflowInstanceStore, IDisposable
{
public WorkflowInstanceStore(string connectionString)
{
_instanceStore = new SqlWorkflowInstanceStore(connectionString);
InstanceHandle handle = _instanceStore.CreateInstanceHandle();
InstanceView view = _instanceStore.Execute(handle,
new CreateWorkflowOwnerCommand(), TimeSpan.FromSeconds(30));
handle.Free();
_instanceStore.DefaultInstanceOwner = view.InstanceOwner;
}
public InstanceStore Store
{
get { return _instanceStore; }
}
public void Dispose()
{
if (null != _instanceStore)
{
var deleteOwner = new DeleteWorkflowOwnerCommand();
InstanceHandle handle = _instanceStore.CreateInstanceHandle();
_instanceStore.Execute(handle, deleteOwner, TimeSpan.FromSeconds(10));
handle.Free();
}
}
private InstanceStore _instanceStore;
}
you can find the best practices to create instance store handle in this link
Workflow Instance Store Best practices
This is an old thread but I just stumbled on the same issue.
Damir's Corner suggests to check if the instance handle is still valid before calling the instance store. I hereby quote the whole post:
Certain aspects of Workflow Foundation are still poorly documented; the persistence framework being one of them. The following snippet is typically used for setting up the instance store:
var instanceStore = new SqlWorkflowInstanceStore(connectionString);
instanceStore.HostLockRenewalPeriod = TimeSpan.FromSeconds(30);
var instanceHandle = instanceStore.CreateInstanceHandle();
var view = instanceStore.Execute(instanceHandle,
new CreateWorkflowOwnerCommand(), TimeSpan.FromSeconds(10));
instanceStore.DefaultInstanceOwner = view.InstanceOwner;
It's difficult to find a detailed explanation of what all of this
does; and to be honest, usually it's not necessary. At least not,
until you start encountering problems, such as InstanceOwnerException:
The execution of an InstancePersistenceCommand was interrupted because
the instance owner registration for owner ID
'9938cd6d-a9cb-49ad-a492-7c087dcc93af' has become invalid. This error
indicates that the in-memory copy of all instances locked by this
owner have become stale and should be discarded, along with the
InstanceHandles. Typically, this error is best handled by restarting
the host.
The error is closely related to the HostLockRenewalPeriod property
which defines how long obtained instance handle is valid without being
renewed. If you try monitoring the database while an instance store
with a valid instance handle is instantiated, you will notice
[System.Activities.DurableInstancing].[ExtendLock] being called
periodically. This stored procedure is responsible for renewing the
handle. If for some reason it fails to be called within the specified
HostLockRenewalPeriod, the above mentioned exception will be thrown
when attempting to persist a workflow. A typical reason for this would
be temporarily inaccessible database due to maintenance or networking
problems. It's not something that happens often, but it's bound to
happen if you have a long living instance store, e.g. in a constantly
running workflow host, such as a Windows service.
Fortunately it's not all that difficult to fix the problem, once you
know the cause of it. Before using the instance store you should
always check, if the handle is still valid; and renew it, if it's not:
if (!instanceHandle.IsValid)
{
instanceHandle = instanceStore.CreateInstanceHandle();
var view = instanceStore.Execute(instanceHandle,
new CreateWorkflowOwnerCommand(), TimeSpan.FromSeconds(10));
instanceStore.DefaultInstanceOwner = view.InstanceOwner;
}
It's definitely less invasive than the restart of the host, suggested
by the error message.
you have to be sure about expiration of owner user
here how I am used to handle this issue
public SqlWorkflowInstanceStore SetupSqlpersistenceStore()
{
SqlWorkflowInstanceStore sqlWFInstanceStore = new SqlWorkflowInstanceStore(ConfigurationManager.ConnectionStrings["DB_WWFConnectionString"].ConnectionString);
sqlWFInstanceStore.InstanceCompletionAction = InstanceCompletionAction.DeleteAll;
InstanceHandle handle = sqlWFInstanceStore.CreateInstanceHandle();
InstanceView view = sqlWFInstanceStore.Execute(handle, new CreateWorkflowOwnerCommand(), TimeSpan.FromSeconds(30));
handle.Free();
sqlWFInstanceStore.DefaultInstanceOwner = view.InstanceOwner;
return sqlWFInstanceStore;
}
and here how you can use this method
wfApp.InstanceStore = SetupSqlpersistenceStore();
wish this help
[I am new to ADO.NET and the Entity Framework, so forgive me if this questions seems odd.]
In my WPF application a user can switch between different databases at run time. When they do this I want to be able to do a quick check that the database is still available. What I have easily available is the ObjectContext. The test I am preforming is getting the count on the total records of a very small table and if it returns results then it passed, if I get an exception then it fails. I don't like this test, it seemed the easiest to do with the ObjectContext.
I have tried setting the connection timeout it in the connection string and on the ObjectConntext and either seem to change anything for the first scenario, while the second one is already fast so it isn't noticeable if it changes anything.
Scenario One
If the connect was down when before first access it takes about 30 seconds before it gives me the exception that the underlying provider failed.
Scenario Two
If the database was up when I started the application and I access it, and then the connect drops while using the test is quick and returns almost instantly.
I want the first scenario described to be as quick as the second one.
Please let me know how best to resolve this, and if there is a better way to test the connectivity to a DB quickly please advise.
There really is no easy or quick way to resolve this. The ConnectionTimeout value is getting ignored with the Entity Framework. The solution I used is creating a method that checks if a context is valid by passing in the location you which to validate and then it getting the count from a known very small table. If this throws an exception the context is not valid otherwise it is. Here is some sample code showing this.
public bool IsContextValid(SomeDbLocation location)
{
bool isValid = false;
try
{
context = GetContext(location);
context.SomeSmallTable.Count();
isValid = true;
}
catch
{
isValid = false;
}
return isValid;
}
You may need to use context.Database.Connection.Open()
I am trying to register to a "Device added/ Device removed" event using WMI. When I say device - I mean something in the lines of a Disk-On-Key or any other device that has files on it which I can access...
I am registering to the event, and the event is raised, but the EventType propery is different from the one I am expecting to see.
The documentation (MSDN) states : 1- config change, 2- Device added, 3-Device removed 4- Docking. For some reason I always get a value of 1.
Any ideas ?
Here's sample code :
public class WMIReceiveEvent
{
public WMIReceiveEvent()
{
try
{
WqlEventQuery query = new WqlEventQuery(
"SELECT * FROM Win32_DeviceChangeEvent");
ManagementEventWatcher watcher = new ManagementEventWatcher(query);
Console.WriteLine("Waiting for an event...");
watcher.EventArrived +=
new EventArrivedEventHandler(
HandleEvent);
// Start listening for events
watcher.Start();
// Do something while waiting for events
System.Threading.Thread.Sleep(10000);
// Stop listening for events
watcher.Stop();
return;
}
catch(ManagementException err)
{
MessageBox.Show("An error occurred while trying to receive an event: " + err.Message);
}
}
private void HandleEvent(object sender,
EventArrivedEventArgs e)
{
Console.WriteLine(e.NewEvent.GetPropertyValue["EventType"]);
}
public static void Main()
{
WMIReceiveEvent receiveEvent = new WMIReceiveEvent();
return;
}
}
Well, I couldn't find the code. Tried on my old RAC account, nothing. Nothing in my old backups. Go figure. But I tried to work out how I did it, and I think this is the correct sequence (I based a lot of it on this article):
Get all drive letters and cache
them.
Wait for the WM_DEVICECHANGE
message, and start a timer with a
timeout of 1 second (this is done to
avoid a lot of spurious
WM_DEVICECHANGE messages that start
as start as soon as you insert the
USB key/other device and only end
when the drive is "settled").
Compare the drive letters with the
old cache and detect the new ones.
Get device information for those.
I know there are other methods, but that proved to be the only one that would work consistently in different versions of windows, and we needed that as my client used the ActiveX control on a webpage that uploaded images from any kind of device you inserted (I think they produced some kind of printing kiosk).
Oh! Yup, I've been through that, but using the raw Windows API calls some time ago, while developing an ActiveX control that detected the insertion of any kind of media. I'll try to unearth the code from my backups and see if I can tell you how I solved it. I'll subscribe to the RSS just in case somebody gets there first.
Well,
u can try win32_logical disk class and bind it to the __Instancecreationevent.
You can easily get the required info
I tried this on my system and I eventually get the right code. It just takes a while. I get a dozen or so events, and one of them is the device connect code.