Hi Ikai, Any updates? (I see there's a mention of adding grabTail in the 1.3.1 release notes - though it has been there in 1.3.0 already)
In the meantime, I have implemented the queue with a head/tail pointer, using the increment call... This works, but if grabTail worked as advertised, that would be more elegant. Regards, Viktor On Feb 2, 7:28 pm, "Ikai L (Google)" <[email protected]> wrote: > That's interesting. Let me follow up with the team to try to understand how > this is supposed to work. > > > > > > On Tue, Feb 2, 2010 at 12:05 AM, phraktle <[email protected]> wrote: > > > Plus, it's working okay in the development server :) > > > V. > > > On Feb 2, 9:03 am, phraktle <[email protected]> wrote: > > > Hi, > > > > In this case grabTail would be quite useless, as one cannot really > > > construct queues with it (ie. it would just force removing items from > > > all namespaces that wouldn't even expire otherwise). The documentation > > > also implies that there's a separate LRU list per namespace, which > > > does make sense, but is not what's happening in production: > > > >http://code.google.com/appengine/docs/java/javadoc/com/google/appengi.. > > .) > > > > "Grabs (atomically get and delete) items off the tail of LRU list. > > > This can be used to implement queue system with high throughput and > > > low latency, but low reliability. Current namespace should be set and > > > not empty for the service. For each namespace memcache maintains a > > > separate LRU list." > > > > Regards, > > > Viktor > > > > On Feb 1, 9:22 pm, "Ikai L (Google)" <[email protected]> wrote: > > > > > I'll raise the issue with some other members of the team, but it seems > > like > > > > this is working as expected. A memcache namespace is nothing more than > > a > > > > prefix applied to a memcache key. There's no true partitioning > > mechanism > > > > within memcache. grabTail simply returns the item that would be expired > > by > > > > the LRU mechanism if memcache needed more space. There isn't a > > different > > > > "queue" per namespace, only a "queue" for global expirations. > > > > > On Mon, Feb 1, 2010 at 4:29 AM, phraktle <[email protected]> wrote: > > > > > Hi, > > > > > > On production, grabTail returns objects from other namespaces. This > > is > > > > > a significant problem that > > > > > makes grabTail (thus queue-like usage) unusable. > > > > > > I filed this as a bug, with a very simple example here: > > > > >http://code.google.com/p/googleappengine/issues/detail?id=2706 > > > > > > Can you please look into this? I don't even see a workaround that I > > > > > can implement in the meantime... > > > > > > Thanks, > > > > > Viktor > > > > > > -- > > > > > 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]<google-appengine-java%2B > > > > > [email protected]><google-appengine-java%2B > > [email protected]> > > > > > . > > > > > For more options, visit this group at > > > > >http://groups.google.com/group/google-appengine-java?hl=en. > > > > > -- > > > > Ikai Lan > > > > Developer Programs Engineer, Google App Enginehttp:// > > googleappengine.blogspot.com|http://twitter.com/app_engine > > > -- > > 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]<google-appengine-java%2B > > [email protected]> > > . > > For more options, visit this group at > >http://groups.google.com/group/google-appengine-java?hl=en. > > -- > Ikai Lan > Developer Programs Engineer, Google App > Enginehttp://googleappengine.blogspot.com|http://twitter.com/app_engine -- 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.
