I wouldnt suggest Memcache for this purpose as memcache doesnt guarntee that what you put in it will be available after 30 seconds. Memcach can be flushed because of number of reasons. And memcache defnitely will not be scalable, if your number of ysers goes high then least used entries will be deleted automatically even if that entry comes under criteria of last 30 seconds.
I think your first thought about using datastore is good enough. Why do you think Datastore will not be scalable? May be you can explain your problem statement bit more. On Jun 23, 9:11 am, "l.denardo" <[email protected]> wrote: > I'm just giving a not-well-thought suggestion, but I'd rather use > memcache for this. > > I guess something like using a time-dependent code as the key (i.e. a > counter which increments every 30 seconds) and a list of user ids as > the value, and simply doing a get() on the cache for the current > counter value would work. > > I don't know how this could scale, due to concurrent updates, but I > definitely think Memcache is the way to go, not datastore. > > Regards > Lorenzo > > On Jun 23, 5:45 am, Ryan <[email protected]> wrote: > > > > > Each of my users is polling the server every few seconds. I need to > > keep a list of the users that have polled in the last 30 seconds handy > > for a task I have queued to run every few seconds. > > > The obvious way I see to do it is to update a datastore entry every > > time the user polls, and query the entries that have a timestamp > > within the last N seconds within my task queue. I can't imagine this > > scaling well. > > > Any recommendations? > > > Thanks.- Hide quoted text - > > - Show quoted text - -- You received this message because you are subscribed to the Google Groups "Google App Engine" 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?hl=en.
