> Let me first say that I don't have a lot of practical experience with
> threading, I've read lots about and I get the concepts, but that's about
it.

> I need to create a service that polls a database every couple of seconds
and
> acts on a result set if need be.  I don't care about any other program
> communicating with the service, it just needs to up 24/7 and working.  To
> implement this polling I created an instance of System.Timers.Timer and I
> added code to the Elapsed event handler.

> I noticed that this timer is re-entrant, so if my interval is set to 1
> second and the unit of work that needs to be performed in the elapsed
event
> takes 3 seconds, then the service will spin up 2 more threads and run the
> elapsed event handler on each one.  As you can imagine this is not how I
> want things to run.

> As a workaround I call the Stop method on the timer as the first statement
> in my elapsed event handler, then I call Start as the last statement.  For
> obvious reasons this stops the timer from being re-entrant and assures
that
> only one thread is polling the database at a time.

> Is this approach totally bogus, am I making this much harder than it needs
> to be?

> TIA

> Cheers

> --
> Robert Chapman, MCSD
> Manager, Applications Development
> prairieFyre Software Inc.
> http://www.prairiefyre.com

> Why don't you start your procedure that checks the database on its own
> thread and then use the Sleep(milliseconds) method to put the thread to
> sleep for the 5 seconds or whatever between checks of the database.
Sounds
> like this would be cleaner.

> HTH
> Tom

> > Let me first say that I don't have a lot of practical experience with
> > threading, I've read lots about and I get the concepts, but that's about
> it.

> > I need to create a service that polls a database every couple of seconds
> and
> > acts on a result set if need be.  I don't care about any other program
> > communicating with the service, it just needs to up 24/7 and working.
To
> > implement this polling I created an instance of System.Timers.Timer and
I
> > added code to the Elapsed event handler.

> > I noticed that this timer is re-entrant, so if my interval is set to 1
> > second and the unit of work that needs to be performed in the elapsed
> event
> > takes 3 seconds, then the service will spin up 2 more threads and run
the
> > elapsed event handler on each one.  As you can imagine this is not how I
> > want things to run.

> > As a workaround I call the Stop method on the timer as the first
statement
> > in my elapsed event handler, then I call Start as the last statement.
For
> > obvious reasons this stops the timer from being re-entrant and assures
> that
> > only one thread is polling the database at a time.

> > Is this approach totally bogus, am I making this much harder than it
needs
> > to be?

> > TIA

> > Cheers

> > --
> > Robert Chapman, MCSD
> > Manager, Applications Development
> > prairieFyre Software Inc.
> > http://www.prairiefyre.com