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.netvb.netwindows-servicesmsmqpeek

How do I subscribe to a MSMQ queue but only "peek" the message in .Net?


We have a MSMQ Queue setup that receives messages and is processed by an application. We'd like to have another process subscribe to the Queue and just read the message and log it's contents.

I have this in place already, the problem is it's constantly peeking the queue. CPU on the server when this is running is around 40%. The mqsvc.exe runs at 30% and this app runs at 10%. I'd rather have something that just waits for a message to come in, get's notified of it, and then logs it without constantly polling the server.

    Dim lastid As String
    Dim objQueue As MessageQueue
    Dim strQueueName As String

    Public Sub Main()
        objQueue = New MessageQueue(strQueueName, QueueAccessMode.SendAndReceive)
        Dim propertyFilter As New MessagePropertyFilter
        propertyFilter.ArrivedTime = True
        propertyFilter.Body = True
        propertyFilter.Id = True
        propertyFilter.LookupId = True
        objQueue.MessageReadPropertyFilter = propertyFilter
        objQueue.Formatter = New ActiveXMessageFormatter
        AddHandler objQueue.PeekCompleted, AddressOf MessageFound

        objQueue.BeginPeek()
    end main

    Public Sub MessageFound(ByVal s As Object, ByVal args As PeekCompletedEventArgs)

        Dim oQueue As MessageQueue
        Dim oMessage As Message

        ' Retrieve the queue from which the message originated
        oQueue = CType(s, MessageQueue)

            oMessage = oQueue.EndPeek(args.AsyncResult)
            If oMessage.LookupId <> lastid Then
                ' Process the message here
                lastid = oMessage.LookupId
                ' let's write it out
                log.write(oMessage)
            End If

        objQueue.BeginPeek()
    End Sub

Solution

  • A Thread.Sleep(10) in between peek iterations may save you a bunch of cycles.

    The only other option I can think of is to build the logging into the queue reading application.