Also be aware of https://issues.apache.org/jira/browse/CASSANDRA-7734 if you are using C* 2.0.6+ (2.0.6 introduced a change that can sometimes causes initial schema propagation not to happen, introducing potentially long delays until some other code path repairs it later)
On Sep 30, 2014, at 1:54 AM, Ben Bromhead <b...@instaclustr.com> wrote: > The system.peers table which is a copy of some gossip info the node has > stored, including the schema version. You should query this and wait until > all schema versions have converged. > > http://www.datastax.com/documentation/cql/3.0/cql/cql_using/use_sys_tab_cluster_t.html > > http://www.datastax.com/dev/blog/the-data-dictionary-in-cassandra-1-2 > > As ensuring that the driver keeps talking to the node you made the schema > change on I would ask the drivers specific mailing list / IRC: > > MAILING LIST: > https://groups.google.com/a/lists.datastax.com/forum/#!forum/java-driver-user > IRC: #datastax-drivers on irc.freenode.net > > > On 30 September 2014 10:16, Clint Kelly <clint.ke...@gmail.com> wrote: > Hi all, > > I often have problems with code that I write that uses the DataStax Java > driver to create / modify a keyspace or table and then soon after reads the > metadata for the keyspace to verify that whatever changes I made the keyspace > or table are complete. > > As an example, I may create a table called `myTableName` and then very soon > after do something like: > > assert(session > .getCluster() > .getMetaData() > .getKeyspace(myKeyspaceName) > .getTable(myTableName) != null) > > I assume this fails sometimes because the default round-robin load balancing > policy for the Java driver will send my create-table request to one node and > the metadata read to another, and because it takes some time for the table > creation to propagate across all of the nodes in my cluster. > > What is the best way to deal with this problem? Is there a standard way to > wait for schema changes to propagate? > > Best regards, > Clint > > > > -- > Ben Bromhead > > Instaclustr | www.instaclustr.com | @instaclustr | +61 415 936 359 >
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