To clarify a bit: one thread from our server runs one loop with a unique id. each requests stores a value in memcache and returns that value. In the following request, the memcache is queried if the value just written, is in the cache. This sometimes fail.
My fear is that it is due to the requests changing to another app instance and then suddently getting wrong data. instance 1 +++++ +++++ instance 2 -- Hope this clears out the example above a bit Cheers Kim On Jun 17, 7:52 pm, Kim Riber <kimsteenri...@gmail.com> wrote: > Hi, > I'm experiencing some rather strange behavior from memcache. I think > I'm getting different data back from memcache using the same key > The issue I see is that when putting load on our application, even > simple memcache queries are starting to return inconsistant data. When > running the same request from multiple threads, I get different > results. > I've made a very simple example, that runs fine on 1-200 threads, but > if I put load on the app (with some heavier requests) just before I > run my test, I see different values coming back from memcache using > the same keys. > > def get_new_memcahce_value(key, old_value): > old_val = memcache.get(key) > new_val = uuid.uuid4().get_hex() > reply = 'good' > if old_val and old_value != "": > if old_val != old_value: > reply = 'fail' > new_val = old_value > else: > if not memcache.set(key, new_val): > reply = 'set_fail' > else: > reply = 'new' > if not memcache.set(key,new_val): > reply = 'set_fail' > return (new_value, reply) > > and from a server posting requests: > > def request_loop(id): > key = "test:key_%d" % id > val, reply = get_new_memcahce_value(key, "") > for i in range(20): > val,reply = get_new_memcahce_value(key, val) > > Is memcache working localy on a cluster of servers, and if an > application is spawned over more clusters, memcache will not > propergate data to the other clusters? > > I hope someone can clarify this, since I can't find any post regarding > this issue. > > Is there some way to get the application instance ID, so I can do some > more investigation on the subject? > > Thanks > Kim --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~----------~----~----~----~------~----~------~--~---
