We are using Cassandra 2.0.3-1 installed on Ubuntu 12.04 from the DataStax repo with the DataStax Java driver version 2.0.0-rc1. Every now and then we get the following exception:
2013-12-19 06:56:34,619 [sql-2-t15] ERROR core.RequestHandler - Unexpected error while querying /x.x.x.x java.lang.NullPointerException at com.datastax.driver.core.HostConnectionPool.waitForConnection(HostConnectionPool.java:203) at com.datastax.driver.core.HostConnectionPool.borrowConnection(HostConnectionPool.java:107) at com.datastax.driver.core.RequestHandler.query(RequestHandler.java:112) at com.datastax.driver.core.RequestHandler.sendRequest(RequestHandler.java:93) at com.datastax.driver.core.Session$Manager.execute(Session.java:513) at com.datastax.driver.core.Session$Manager.executeQuery(Session.java:549) at com.datastax.driver.core.Session.executeAsync(Session.java:172) This happens during a big data load process which will do up to 256 executeAsync's in parallel. Any ideas? Its not causing huge problems because the operation is just retried by our code but it would be nice to eliminate it.