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Seeking Advice for Starting a Windows ServiceIn my OnStart event I commence a long running process which polls a database table and performs various processing. Since this polling loop is entered synchronously from OnStart, basically the OnStart event doesn't terminate for the life of the program. This doesn't give the SCM the correct feedback that the service has started properly. Consequently, the SCM throws an error dialog and the service is marked as 'Starting', even though the service is in fact running properly. I'd like to correct this. I guess the best practice approach would be to perform initialization synchronously just to make sure that all necessary resources are obtained, and then launch into the main service routine asynchronously so that the OnStart event can terminate in a timely manner. But I'm not sure how to do this. Also, any advice on how the service can execute at a low background priority will be very much appreciated. Thanks for your advice! - Joseph Geretz -
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On Mar 6, 11:14 pm, "Joseph Geretz" <jger...@nospam.com> wrote: Just create a thread in the onstart routine, and perform your work in> I have a Service which runs OK, but I'm abviously not starting it properly. > In my OnStart event I commence a long running process which polls a database > table and performs various processing. Since this polling loop is entered > synchronously from OnStart, basically the OnStart event doesn't terminate > for the life of the program. This doesn't give the SCM the correct feedback > that the service has started properly. Consequently, the SCM throws an error > dialog and the service is marked as 'Starting', even though the service is > in fact running properly. I'd like to correct this. > > I guess the best practice approach would be to perform initialization > synchronously just to make sure that all necessary resources are obtained, > and then launch into the main service routine asynchronously so that the > OnStart event can terminate in a timely manner. But I'm not sure how to do > this. > > Also, any advice on how the service can execute at a low background priority > will be very much appreciated. > > Thanks for your advice! > > - Joseph Geretz - the thread method... You can also set that threads priority. Something like: // do resource aquisition // create your thread, and set the priority, and start it up Thread worker = new Thread (new ThreadStart (WorkerMethod)); worker.Priority = ThreadPriority.BelowNormal; // Or Lowest if you like worker.Start(); Then you just do your actual work in the WorkerMethod. You can signal the thread to end from the OnStop method, etc. HTH -- Tom Shelton
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"Joseph Geretz" <jgeretz@nospam.com> wrote in message Just start a thread in OnStart and set it's priority to be lownews:e$hNq$HYHHA.984@TK2MSFTNGP04.phx.gbl... >I have a Service which runs OK, but I'm abviously not starting it properly. > In my OnStart event I commence a long running process which polls a > database > table and performs various processing. Since this polling loop is entered > synchronously from OnStart, basically the OnStart event doesn't terminate > for the life of the program. This doesn't give the SCM the correct > feedback > that the service has started properly. Consequently, the SCM throws an > error > dialog and the service is marked as 'Starting', even though the service is > in fact running properly. I'd like to correct this. > > I guess the best practice approach would be to perform initialization > synchronously just to make sure that all necessary resources are obtained, > and then launch into the main service routine asynchronously so that the > OnStart event can terminate in a timely manner. But I'm not sure how to do > this. > > Also, any advice on how the service can execute at a low background > priority will be very much appreciated. > > Thanks for your advice! Thread thread = new Thread(new ThreadStart(DoStuff)); thread.Priority = ThreadPriority.Lowest; thread.Start(); Show quote > > - Joseph Geretz - > > > OK, thanks guys - very helpful.
But how do I cancel a thread? I guess I can't just kill the operation. Is cancelling a thread simply setting a flag on the thread and my code needs to monitor that flag to see when it is set in order to terminate? (This seems to be the way it would work for a BackgroundWorker?) Is there any reason to prefer a Thread over a BackgroundWorker object or vice versa? I guess the two approaches would be similar? (Please forgive the basic questions. As an ex-VB6 devleoper, I haven't had much exposure to threads up to this point.) Thanks for your advice. - Joe Geretz - Show quote "Michael C" <nospam@nospam.com> wrote in message news:eahsUSIYHHA.992@TK2MSFTNGP04.phx.gbl... > "Joseph Geretz" <jgeretz@nospam.com> wrote in message > news:e$hNq$HYHHA.984@TK2MSFTNGP04.phx.gbl... >>I have a Service which runs OK, but I'm abviously not starting it >>properly. >> In my OnStart event I commence a long running process which polls a >> database >> table and performs various processing. Since this polling loop is entered >> synchronously from OnStart, basically the OnStart event doesn't terminate >> for the life of the program. This doesn't give the SCM the correct >> feedback >> that the service has started properly. Consequently, the SCM throws an >> error >> dialog and the service is marked as 'Starting', even though the service >> is >> in fact running properly. I'd like to correct this. >> >> I guess the best practice approach would be to perform initialization >> synchronously just to make sure that all necessary resources are >> obtained, >> and then launch into the main service routine asynchronously so that the >> OnStart event can terminate in a timely manner. But I'm not sure how to >> do >> this. >> >> Also, any advice on how the service can execute at a low background >> priority will be very much appreciated. >> >> Thanks for your advice! > > Just start a thread in OnStart and set it's priority to be low > > Thread thread = new Thread(new ThreadStart(DoStuff)); > > thread.Priority = ThreadPriority.Lowest; > > thread.Start(); > > >> >> - Joseph Geretz - >> >> >> > >
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On Mar 7, 8:01 am, "Joseph Geretz" <jger...@nospam.com> wrote: you can use a flag> OK, thanks guys - very helpful. > > But how do I cancel a thread? I guess I can't just kill the operation. Is > cancelling a thread simply setting a flag on the thread and my code needs to > monitor that flag to see when it is set in order to terminate? (This seems > to be the way it would work for a BackgroundWorker?) Is there any reason to > prefer a Thread over a BackgroundWorker object or vice versa? I guess the > two approaches would be similar? (Please forgive the basic questions. As an > ex-VB6 devleoper, I haven't had much exposure to threads up to this point.) > > Thanks for your advice. > > - Joe Geretz - > > "Michael C" <nos...@nospam.com> wrote in message > > news:eahsUSIYHHA.992@TK2MSFTNGP04.phx.gbl... > > > "Joseph Geretz" <jger...@nospam.com> wrote in message > >news:e$hNq$HYHHA.984@TK2MSFTNGP04.phx.gbl... > >>I have a Service which runs OK, but I'm abviously not starting it > >>properly. > >> In my OnStart event I commence a long running process which polls a > >> database > >> table and performs various processing. Since this polling loop is entered > >> synchronously from OnStart, basically the OnStart event doesn't terminate > >> for the life of the program. This doesn't give the SCM the correct > >> feedback > >> that the service has started properly. Consequently, the SCM throws an > >> error > >> dialog and the service is marked as 'Starting', even though the service > >> is > >> in fact running properly. I'd like to correct this. > > >> I guess the best practice approach would be to perform initialization > >> synchronously just to make sure that all necessary resources are > >> obtained, > >> and then launch into the main service routine asynchronously so that the > >> OnStart event can terminate in a timely manner. But I'm not sure how to > >> do > >> this. > > >> Also, any advice on how the service can execute at a low background > >> priority will be very much appreciated. > > >> Thanks for your advice! > > > Just start a thread in OnStart and set it's priority to be low > > > Thread thread = new Thread(new ThreadStart(DoStuff)); > > > thread.Priority = ThreadPriority.Lowest; > > > thread.Start(); > > >> - Joseph Geretz - bool run = true while(run){ // Do some work // Check condition run = false; } Hi Oscar,
> you can use a flag So what you're saying is that when the method which is running on the thread > bool run = true > > while(run){ > // Do some work > // Check condition > run = false; > } terminates, the thread itself is terminated automatically? Thanks for your help, - Joseph Geretz - <oscar.acostamonte***@googlemail.com> wrote in message Show quote news:1173275432.765437.90770@q40g2000cwq.googlegroups.com... > On Mar 7, 8:01 am, "Joseph Geretz" <jger...@nospam.com> wrote: >> OK, thanks guys - very helpful. >> >> But how do I cancel a thread? I guess I can't just kill the operation. Is >> cancelling a thread simply setting a flag on the thread and my code needs >> to >> monitor that flag to see when it is set in order to terminate? (This >> seems >> to be the way it would work for a BackgroundWorker?) Is there any reason >> to >> prefer a Thread over a BackgroundWorker object or vice versa? I guess the >> two approaches would be similar? (Please forgive the basic questions. As >> an >> ex-VB6 devleoper, I haven't had much exposure to threads up to this >> point.) >> >> Thanks for your advice. >> >> - Joe Geretz - >> >> "Michael C" <nos...@nospam.com> wrote in message >> >> news:eahsUSIYHHA.992@TK2MSFTNGP04.phx.gbl... >> >> > "Joseph Geretz" <jger...@nospam.com> wrote in message >> >news:e$hNq$HYHHA.984@TK2MSFTNGP04.phx.gbl... >> >>I have a Service which runs OK, but I'm abviously not starting it >> >>properly. >> >> In my OnStart event I commence a long running process which polls a >> >> database >> >> table and performs various processing. Since this polling loop is >> >> entered >> >> synchronously from OnStart, basically the OnStart event doesn't >> >> terminate >> >> for the life of the program. This doesn't give the SCM the correct >> >> feedback >> >> that the service has started properly. Consequently, the SCM throws an >> >> error >> >> dialog and the service is marked as 'Starting', even though the >> >> service >> >> is >> >> in fact running properly. I'd like to correct this. >> >> >> I guess the best practice approach would be to perform initialization >> >> synchronously just to make sure that all necessary resources are >> >> obtained, >> >> and then launch into the main service routine asynchronously so that >> >> the >> >> OnStart event can terminate in a timely manner. But I'm not sure how >> >> to >> >> do >> >> this. >> >> >> Also, any advice on how the service can execute at a low background >> >> priority will be very much appreciated. >> >> >> Thanks for your advice! >> >> > Just start a thread in OnStart and set it's priority to be low >> >> > Thread thread = new Thread(new ThreadStart(DoStuff)); >> >> > thread.Priority = ThreadPriority.Lowest; >> >> > thread.Start(); >> >> >> - Joseph Geretz - > > you can use a flag > bool run = true > > while(run){ > // Do some work > // Check condition > run = false; > } > >
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On Mar 7, 8:26 am, "Joseph Geretz" <jger...@nospam.com> wrote: Yes, when a thread method exits - so does the thread. Be a little> Hi Oscar, > > > you can use a flag > > bool run = true > > > while(run){ > > // Do some work > > // Check condition > > run = false; > > } > > So what you're saying is that when the method which is running on the thread > terminates, the thread itself is terminated automatically? > > Thanks for your help, > > - Joseph Geretz - careful using a flag like this though to end the thread - especially if it is going to be set from outside the thread... While on x86 processors, reads and writes of this type are guarenteed to be atomic - you may still get unexpected results. The reason is that sometime the compiler will optimize the code to read from a register instead of the actual memory value. When this happens in a threaded environment, you may set the value to false - but the thread will never see it happen... You have two choices to fix this - one use a lock or declare the bool as volatile (which would be my prefered method in this case :). By declaring it volatile, you tell the compiler that this value maybe changed from an outside source, and to always fetch it from memory. -- Tom Shelton Look here:
http://blogs.msdn.com/bclteam/archive/2005/03/15/396428.aspx I would append his article by saying you want to have a when you start you "actual code" I would kill off the timerDelegate... after you job run, reinstantiate the timerDelegate. Show quote "Joseph Geretz" <jgeretz@nospam.com> wrote in message news:e$hNq$HYHHA.984@TK2MSFTNGP04.phx.gbl... > I have a Service which runs OK, but I'm abviously not starting it properly. > In my OnStart event I commence a long running process which polls a database > table and performs various processing. Since this polling loop is entered > synchronously from OnStart, basically the OnStart event doesn't terminate > for the life of the program. This doesn't give the SCM the correct feedback > that the service has started properly. Consequently, the SCM throws an error > dialog and the service is marked as 'Starting', even though the service is > in fact running properly. I'd like to correct this. > > I guess the best practice approach would be to perform initialization > synchronously just to make sure that all necessary resources are obtained, > and then launch into the main service routine asynchronously so that the > OnStart event can terminate in a timely manner. But I'm not sure how to do > this. > > Also, any advice on how the service can execute at a low background priority > will be very much appreciated. > > Thanks for your advice! > > - Joseph Geretz - > > >  |
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