I've seen a couple of posts here and there on the subject of a locking mechanism for Riak, most notably:
http://riak-users.197444.n3.nabble.com/Riak-and-Locks-td1866960.html While it would only serve as an advisory locking mechanism, wouldn't a bucket with a reasonably high n, w and dw set equal to n, a deterministic naming scheme for the object being locked, and a locking algorithm such as: 1. PUT /locks/object_id If-None-Match: * Body: <some unique identifier for the client thread> 1a. If this fails, wait for a while, then try again. 1b. If it succeeds, proceed to 2. 2. The doc for If-None-Match says "this does not prevent concurrent writes; it is possible for the condition to evaluate to true for multiple requests if the requests occur at the same time." I'm not completely sure if n=w=dw protects me from concurrent writes (I'm not familiar with the locking semantics of a single riak instance). Anyway, if I'm in fact not protected, the next step is to read the value back to make sure we're actually the ones holding the key. If not, go back to step 1. If yes, proceed as planned. 3. Once you're done with the lock, just DELETE it. If this were really that simple, someone would have suggested it. So, what is this Riak rookie (i.e. I) missing? -- Soren Hansen | http://linux2go.dk/ Ubuntu Developer | http://www.ubuntu.com/ OpenStack Developer | http://www.openstack.org/ _______________________________________________ riak-users mailing list riak-users@lists.basho.com http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
