Precision of seconds can be tough, BTW, because syncing clocks is a tough problem that nobody has really solved. The mere act of making an RPC to a backend or Memcache can introduce skew simply because the latency is not predictable. Most of the time (99.999%) there shouldn't be an issue because latency will be in milliseconds, but anything can happen in a distributed environment.
Depending on what it is you are doing, it may be simpler to change your product requirements. A little related: http://en.wikipedia.org/wiki/Lamport_timestamps Not that related but interesting: http://en.wikipedia.org/wiki/Uncertainty_principle Ikai Lan Developer Programs Engineer, Google App Engine Blog: http://googleappengine.blogspot.com Twitter: http://twitter.com/app_engine Reddit: http://www.reddit.com/r/appengine On Tue, Jun 28, 2011 at 12:01 AM, jMotta <[email protected]> wrote: > Loreno, > > I don't know what you mean with "global count down timer", if you want to > trigger an action upon the end of the global count down you can use the * > cron* implementation. > > Can you explain what is the use that you want with this? In "low-level > speaking", the only ways to share state across multiple instances / requests > safety from concurrent access issues and given the cloud nature of it is use > the datastore and memcache. > > *Jayr Motta* > Software Developer > * > * > I'm on > BlackBeltFactory.com<http://www.blackbeltfactory.com/ui#!User/jmotta/ref=jmotta> > ! > > > > On Mon, Jun 27, 2011 at 12:48 PM, [email protected] < > [email protected]> wrote: > >> Is it possible to implement a global count down timer in GAE/J? I would >> like an unique timer to be shared among all the application instances. The >> precision of the timer is seconds. >> >> Any idea? >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Google App Engine for Java" group. >> To post to this group, send email to >> [email protected]. >> To unsubscribe from this group, send email to >> [email protected]. >> For more options, visit this group at >> http://groups.google.com/group/google-appengine-java?hl=en. >> > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine for Java" group. > To post to this group, send email to > [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/google-appengine-java?hl=en. > -- You received this message because you are subscribed to the Google Groups "Google App Engine for Java" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine-java?hl=en.
