That was the trick. Thanks! On Apr 20, 2011, at 6:05 PM, Jonathan Ellis <jbel...@gmail.com> wrote:
> See the comments for describe_schema_versions. > > On Wed, Apr 20, 2011 at 4:59 PM, William Oberman > <ober...@civicscience.com> wrote: >> Hi, >> >> My unit tests started failing once I upgraded from a single node cassandra >> cluster to a full "N" node cluster (I'm starting with 4). I had a few >> various bugs, mostly due to forgetting to read/write at a quorum level in >> places I needed stronger consistency guarantees. But, I kept getting >> random, intermittent failure (the worst kind). I'm 99% sure I see why, >> after some painful debugging, but I don't know what to do about it. The >> basic flaw in my understanding of cassandra seems to boil down to: I thought >> system mutations of keyspaces/column families where of a stronger >> consistency than ONE, but that appears to not be true. Any way for me to >> update a cluster at something more like QUORUM? >> >> The basic idea is in my unit test.setup() I clone my real keyspace as >> keyspace_UUID (with all of the exact same CFs) to get a fresh space to play >> in. In a single node environment, no issues. But, in a cluster, it seems >> that it takes a while for the system_add_keyspace call to propagate. No >> worries I think, I just modify my setup() to do >> describe_keyspace(keyspace_UUID) in a while loop until the cluster is >> ready. My random failures drop considerably, but every once and awhile I >> see a similar kind of failure. Then I find out that schema updates seem to >> propagate on a per node basis. At least, that's what I have to assume as >> I'm using phpcassa which uses a connection pool, and I see in my logging >> that my setup() succeeds because one connection in the pool sees the new >> keyspace, but when my tests run I grab a connection from the pool that is >> missing it! >> >> Do I have a solution other than changing my setup yet again to loop over all >> cassandra servers doing a describe_keyspace()? >> >> -- >> Will Oberman >> Civic Science, Inc. >> 3030 Penn Avenue., First Floor >> Pittsburgh, PA 15201 >> (M) 412-480-7835 >> (E) ober...@civicscience.com >> > > > > -- > Jonathan Ellis > Project Chair, Apache Cassandra > co-founder of DataStax, the source for professional Cassandra support > http://www.datastax.com
