Hi guys,
Getting a strange error intermittently on one of our production sites and
wondering whether you could shed some light on it.

System.Exception: Exception thrown initializing DBSystemValues collection
---> System.Web.HttpException: Failed to map the path '/log/'.
   at
System.Web.Hosting.ISAPIWorkerRequestInProcForIIS6.MapPathSlowUsingIISCore(String path)
   at System.Web.Hosting.ISAPIWorkerRequest.MapPath(String path)
   at System.Web.HttpRequest.MapPath(String virtualPath, String
baseVirtualDir, Boolean allowCrossAppMapping)
   at System.Web.HttpRequest.MapPath(String virtualPath)

As you can see we are initialising a little collection of important system
items one of them being the log file path and we get this error. This only
happens very occasionaly but is a little concerning.

Wondering whether anyone else had noticed this MapPathSlowUsingIISCore error
before?

Thanks

bump

I think i figured out what's causing this, although i don't have a solution.
The problem is caused when a worker thread doesn't get destroyed when the
application domain gets restarted.

In our application the main thread of the app domain creates a second worker
thread that reads a file every 10 seconds. The worker thread needs to call
MapPath, which isn't normally available in a new thread, but i got around
that by manually setting HttpContext.Current inside the worker thread. Here's
a very simple cut down version of what's happening.

Private Shared _httpContext As HttpContext
Private Shared _workerThread As New Thread(AddressOf Run)

Private Shared Sub StartWorkerThread()
    _httpContext = HttpContext.Current
    _workerThread.Start()
End Sub

Private Shared Sub Run()
    HttpContext.Current = _httpContext
    While (True)
        Try
            HttpContext.MapPath(_nextFile)
            DoSomething()
            Sleep(10000)
        Catch ex As ThreadAbortException
            Exit While
        End Try
    End While
End Sub

In development and testing it works fine. The problem only occurs on the
production machine. It only happens sometimes, but when the app domain is
restarted (editing web.config, or uploading a new dll), it seems as though
the worker thread does not get a ThreadAbortException thrown in it. This
means that the worker thread from the old app domain keeps running and trying
to call mappath even though the everything else in the old app domain has
been deleted. It's this old thread that causes the MapPathSlowUsingIISCore
exception.

In the mean time a new app domain, with a new worker thread, has started
running and is operating fine, but the old worker thread is still ticking
away in the background chewing up resources.

So in summary.
The MapPathSlowUsingIISCore exception is merely a side effect of worker
threads not dying when the app domain is restarted.
That's great, except now i have to figure out how to make sure the worker
thread dies.

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