On Saturday, February 20, 2016, Sorin Manolache <sor...@gmail.com> wrote:
> Hello, > > I can set a watch on an object in librados. Does this object have to exist > already at the moment I'm setting the watch on it? What happens if the > object does not exist? Is my watcher valid? Will I get notified when > someone else creates the missing object that I'm watching and sends a > notification? I believe a watch implicitly creates the object, but you could run it on a non-existent object and check. ;) but... > > If the watch is not valid if the object has not yet been created then how > can I get notified when the object is created? (I can imagine a > work-around: there's an additional object, a kind of object registry object > (the equivalent of a directory in a file system), that contains the list of > created objects. I'm watching for modifications of the object registry > object. Whenever a new object is created, the agent that creates the object > also updates the object registry object.) This is probably a better idea. Watches have a bit of overhead and while you can have a few per client without much trouble; if you're trying to watch a whole bunch of potential objects you probably want a stronger side channel communications system anyway, so using a set of communication objects and pushing the relevant data through them is likely to work better. -Greg > > Thank you, > Sorin > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >
_______________________________________________ ceph-users mailing list ceph-users@lists.ceph.com http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
