tracker issue : CF-4028272

CF duplicates IIS requests. Steps to reproduce:

Application.cfc:
----------------
component {
  THIS.name = "ticket_CFDuplicatesIISRequests";
  void function onRequest() {
    cfsetting(requesttimeout=120);
    for(var i=1; i<120; i++) {
      sleep(1000);
    }
  }
}

index.cfm
---------
empty file

1) While above code is running, do the following:
2) In CF's Server Monitor, go to "Active Requests" and see the running request
3) In the Windows Task Manager, end the w3wp.exe process ID* for the associated application pool
4) In CF's Server Monitor, go to "Active Requests" and see the running request was duplicated (bad)
5) Continually repeat #3 and see request is continually duplicated (bad)

To find the w3wp.exe process ID, click the server node at the left side of IIS, then click Worker Processes at the right, then see the process ID associated w/ the application pool.

By default, IIS has health monitoring pings enabled (a per application pool setting). If it is unable to ping an application pool's w3wp.exe process w/in 90 seconds (default value), it deems the process is unhealthy and moves its request queue to a replacement w3wp.exe process and terminates the 'unhealthy' one. Basically, if there is a performance issue on the CF side, and IIS's pings timeout, then IIS follows the described procedure. IIS does this so that users are unaware of the crash.

The issue is that CF's IIS connector is apparently unable to detect that the already-running requests have simply been moved to a replacement process. So, CF treats these moved requests as new requests.

This can become a spiraling performance issue, where an already-burdened CF becomes even more burdened as it is flooded w/ these duplicate requests.

Of course I hope the above issue can be resolved. Additionally, here a suggestion for the future: An onRequestStart() in Server.cfc would be helpful when CF/IIS issues like this arise. We can use IIS's appcmd.exe to get each request's underlying process ID as well as determine if a previous process ID is still active. Using that info, we can filter out these duplicate requests. It'd just be cleaner to deal w/ this in Server.cfc instead of Application.cfc. I'm not asking for a full-blown firewall baked-in, but a Server-level hook would be nice.

----------------------------- Additional Watson Details -----------------------------

Watson Bug ID:	4028272

External Customer Info:
External Company:  
External Customer Name: Aaron
External Customer Email:  
External Test Config: Tested on Windows 2012 R2 w/ CF11 Update 5.

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