I think you found a bug; it should be volatile. (Cassandra does already make sure that only one change runs internally at a time.)
Can you create a ticket? On Fri, Apr 15, 2011 at 6:04 PM, Jeffrey Wang <jw...@palantir.com> wrote: > Hey all, > > > > I’ve been seeing a very rare issue with schema change conflicts on 0.7.3 (I > am serializing all schema changes to a single Cassandra node and waiting for > them to finish before continuing). Occasionally a node in the cluster will > never report the correct schema, and I think it may have to do with > synchronization on DatabaseDescriptor.defsVersion. > > > > As far as I can tell, it is a static variable accessed by multiple threads > but is not protected by synchronized/volatile. I was able to write a test in > which one thread never reads the modification done by another thread (as is > expected by an unsynchronized variable). Should this be fixed or is there a > higher level reason this does not need to be synchronized (in which case I > should continue looking for the reason why my schemas don’t agree)? Thanks. > > > > -Jeffrey > > -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
