Cancelling a Thread due to hung Db call

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I've designed and made a prototype application for a high performance, multi-threaded mail merge to run as a Windows Service (C#). This question refers to one sticky part of the problem, what to do if the process hangs on a database call. I have researched this a lot. I have read a lot of articles about thread cancellation and I ultimately only see one way to do this, thread.Abort(). Yes, I know, absolutely do not use Thread.Abort(), so I have been researching for days how to do it another way and as I see it, there is no alternative. I will tell you why and hopefully you can tell me why I am wrong.

FYI, these are meant as long running threads, so the TPL would make them outside the ThreadPool anyway.

TPL is just a nice wrapper for a Thread, so I see absolutely nothing a Task can do that a Thread cannot. It's just done differently.

Using a thread, you have two choices for stopping it. 1. Have the thread poll in a processing loop to see if a flag has requested cancellation and just end the processing and let the thread die. No problem. 2. Call Thread.Abort() (then catch the exception, do a Join and worry about Finally, etc.)

This is a database call in the thread, so polling will not work once it is started.

On the other hand, if you use TPL and a CancellationToken, it seems to me that you're still polling and then creating an exception. It looks like the same thing I described in case 1 with the thread. Once I start that database call (I also intend to put a async / await around it), there is no way I can test for a change in the CancellationToken. For that matter, the TPL is worse as calling the CancellationToken during a Db read will do exactly nothing, far less than a Thread.Abort() would do.

I cannot believe this is a unique problem, but I have not found a real solution and I have read a lot. Whether a Thread or Task, the worker thread has to poll to know it should stop and then stop (not possible when connected to a Db. It's not in a loop.) or else the thread must be aborted, throwing a ThreadAbortedException or a TaskCanceledException.

My current plan is to start each job as a longrunning thread. If the thread exceeds the time limit, I will call Thread.Abort, catch the exception in the thread and then do a Join() on the thread after the Abort().

I am very, very open to suggestions... Thanks, Mike

I will put this link, because it claims to do this, but I'm having trouble figuring it out and there are no replys to make me think it will work multi-threading-cross-class-cancellation-with-tpl

asked 41 secs ago

Miguelito

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