I have at times experienced definite clock skews (I documented some up as much a minute in the early stages.)
I personally think it is a mistake to design a solution that needs < 5 sec clock accuracy with appengine. T On Saturday, November 2, 2013 12:32:43 PM UTC+8, Vinny P wrote: > > On Fri, Nov 1, 2013 at 9:44 PM, Kaan Soral <kaan...@gmail.com<javascript:> > > wrote: > >> I've been seeing the errors pop up, but it's always between datetime's >> that differ only by 2-3 seconds >> Than I remembered a *really* old discussion about instance time >> differences and it seems that the cause of these 2-3 second differences is >> instance time differences. Could this be the case? >> > > > Yes. > > Instance clocks are not guaranteed to be accurate - there is always some > skew, especially for large applications which span many instances ( in the > physical sense, span multiple machines which may have some clock drift ). > It's rarely mentioned though, since few applications need that accurate of > a clock. > > > On Fri, Nov 1, 2013 at 9:44 PM, Kaan Soral <kaan...@gmail.com<javascript:> > > wrote: > >> I'm thinking of logging an error only-if the difference is >some_seconds, >> however unsure how many seconds that should be, is there an upper limit to >> this time difference, if it exists? >> >> > > When App Engine was still in beta, I personally noted clock skews > exceeding 30 seconds, sometimes close to a minute. With that said, instance > clocks seem to be synchronized to a much closer standard nowadays. If I had > to suggest an upper limit for you, I would go with around 10-15 seconds. > Note that I'm not claiming this to be a hard and fast number - it's my > rough approximation. Feel free to ignore it or go with a lower number. > > > ----------------- > -Vinny P > Technology & Media Advisor > Chicago, IL > > App Engine Code Samples: http://www.learntogoogleit.com > > -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To unsubscribe from this group and stop receiving emails from it, send an email to google-appengine+unsubscr...@googlegroups.com. To post to this group, send email to google-appengine@googlegroups.com. Visit this group at http://groups.google.com/group/google-appengine. For more options, visit https://groups.google.com/groups/opt_out.
