That shouldn't be a problem. Check and update the version number in a
transaction. If the transaction succeeds then it performs the task because
it was the instance that updated the version otherwise if it fails due to a
ConcurrentModificationException than some other instance is carrying out the
task and it doesn't due anything.

On Wed, Feb 9, 2011 at 5:36 PM, Tim Hoffman <[email protected]> wrote:

> Be carefull, because you could run into a dogpile effect.
> Multiple new instances start at the same time and the version number you
> have stored hasn't been updated and all instances try and perform the task
> at the same time.
>
> I think It would be much more reliable to wrap your deploy script to invoke
> a handler after completion of the deployment.
>
> Rgds
>
> T
>
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